Albert Einstein

Concepts are simply empty when they stop being firmly linked to experiences. They resemble upstarts who are ashamed of their origins and want to disown them." The letter was published in the Collected Papers of Albert Einstein, vol 10, doc 66, pp 323-324 (CPAE Translation, vol 10, doc 66, p 201). Slightly uneven toning, a few spots in upper margin, two-hole punch at left margin, folding creases..

do it the way you did. But this is less simple, less natural." He goes on to assert that "[t]he naturalness of the field of structure envisaged by me seems indisputable to me. I will only know in a few months whether this construction contains deeper traits of reality; for the problems needed to be solved to make this decision are not at all easy." The letter ends with a postscript in Einstein's hand, inviting Reichenbach and his wife to tea, noting "Schrödinger is supposed to come as well.".

[…]“ 
11 September 1951: "I have read your letter […] and have looked at your drawings, but I cannot judge them either in a positive or a negative sense. The fact that currents can act on muscles is well known. However, whether you can achieve a health-promoting effect in the way you have suggested, I have no judgment. […]" 

Einstein received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory..

Selig Brodetzky (1888-1954) was second president of the Hebrew University during a turbulent period, marked by the forced abandonment of the campus on Mount Scopus and disputes with the University Senate..

I believe that transnationally minded intellectuals can only serve the good cause effectively by advocating negotiation, understanding and transnational solution of the security problem, but not by engaging in such propaganda ventures as the present one. I find that the Quacker organization [sic!] and the Indian government have served the supranational interests best so far. I think that one should first and foremost stick to the old medical motto: 'Non nocere.'" In fine condition, with some chipping along the edges. Hadamard published an open letter to Einstein in March 1952, accusing the Americans of developing biological weapons for use during the Korean War. Einstein responded privately on March 26, 1952, writing in a letter that has since been published: 'I am really the last person who would excuse these abominable weapons, whether they are atomic bombs or biological means of destruction.' Einstein went on to urge constructive supranational security action. Hadamard evidently asked to publish the letter, which Einstein here declines. A fascinating piece of correspondence between leading intellectuals on the topic of international peace..

This is infinitely more difficult for specialized professionals than for workers in industry and the trades. The services of the American Committee are now needed more than ever before. Many of the professionals who arrived here during the last few years under the Displaced persons Act first gladly accepted low-level jobs if no others were available. They hoped that within a reasonable time they would get a start in their own fields. Unfortunately, all too many are still in their first low level jobs and have become increasingly hopeless. Additional professionals will soon arrive among the 214000 immigrants authorized by the Act recently passed by Congress with the strong support of President Eisenhower. Both the newcomers and those among the earlier arrivals not yet placed have to depend on the American Committee lest their skills are to be lost for our country. I therefore feel strongly that the American Committee should be given the continuing support of understanding American citizens and institutions […] May I express the personal hope that you will be able to contribute to the success of this important endeavor? […]“.

So verhält es sich im Besonderen auch mit den Begriffen Bewegung, Raum, Zeit. Die Relativitätstheorie ist jene physikalische Theorie, die auf einer konsequenten physikalischen Interpretation dieser drei Begriffe beruht. Der Name ‘Relativitätstheorie’ hängt damit zusammen, dass Bewegung vom Standpunkt der Erfahrbarkeit stets als relative Bewegung eines Dinges gegen andere (z. B. eines Wagens gegenüber dem Erdboden, oder der Erde gegenüber der Sonne und den Fixsternen) auftritt (Bewegung ist aber nicht wahrnehmbar als ‘Bewegung gegen den Raum’ oder – wie man es auch ausgedrückt hat – als ‘absolute Bewegung’). Das ‘Relativitätsprinzip’ im weitesten Sinne ist in der Aussage enthalten: Die Gesamtheit der physikalischen Phänomene ist so beschaffen, dass sie für die Aufstellung des Begriffes ‘absolute Bewegung’ keinen Anhalt bietet, oder kürzer aber weniger präzis: Es gibt keine absolute Bewegung [...]". – Traces of a paperclip with a slight rustmark to the first leaf..

Lotte Marx ist in dem Buch „Journey of Hope and Despair: Volume I. Rise and Fall" von Rudolf Hugo Moos erwähnt. Moos arbeitet darin die Geschichte seines Großvaters Rudolf Moos (1866-1951) war ein Cousin zweiten Grades von Albert Einstein. Als Unternehmer entwickelte er die Marken Salamander, Puma und Fasan. Bis 1933 war Albert Einstein mit seiner zweiten Ehefrau Elsa gern gesehener Gast in der Villa der Familie Moos in Nowawes in der Nähe von Potsdam. Einstein war es auch, der Moos, der jüdischer Herkunft war, und seiner Familie 1939 die Ausreise aus Deutschland ermöglichte. Lotte Marx war in der Villa in Potsdam zu Gast. Erwähnt ist sie anlässlich des 62. Geburtstags im November 1929: „[...] Many friends and relatives sent me greetings and best wishes, and we had a large dinner party in the evening. Our guests included Fritz Heinrichsdorff, Karl and Adele Heinrichsdorff, Helene Einstein, Helene Steiner, and Lotte Marx. We had a stimulating conversation, and then, as always, there was time for dancing. […] Helene Steiner visited us in November 1931 and told us about her niece, Lotte Marx. She had been having an extended affair with the son of Fritz Stahl, the wellknown composer, and she was now living with him. [...]" Am 28. Juni 1929 verlieh die Deutsche Physikalische Gesellschaft Max Planck und Einstein die Max-Planck-Medaille. Genau 50 Jahre zuvor hatte Planck als 21-Jähriger in München seine Doktorwürde erhalten. Auf dem Weg zum Physikalischen Institut musste Einstein an fast 1.000 grölenden nationalsozialistischen Studenten vorbei. Diesen Tag hatten Regierung und Reichspräsident zum „Tag der Trauer" ausgerufen: Zehn Jahre zuvor hatten die Deutschen Unterhändler in Versailles den Friedensvertrag unterzeichnet. Vor dem zunehmenden Antisemitismus flüchtete Einstein in die USA. Seit den 1930er Jahren war Albert Einstein weltweit bekannt. Wo er auftrat, wo er sprach, waren die Menschen begeistert. Im Dezember 1932 führte ihn eine Reise in die USA, von der er nach der Machtübernahme des NS-Regimes nicht mehr zurückkehrte. 1933 folgte der Austritt aus der Akademie der Wissenschaften und der Berliner Universität als Reaktion auf die Machtergreifung der Nationalsozialisten. Im Oktober 1940 nahm er die amerikanische Staatsbürgerschaft an. Eine Anekdote am Rande: Als Einstein 1931 während einer USA-Reise an der Premiere von Charlie Chaplin bei einer Filmpremiere von „Lichter der Großstadt" traf, soll es zu folgendem Dialog gekommen sein: Albert Einstein soll gesagt haben, „was ich an Ihrer Kunst am meisten bewundere, ist ihre Universalität. Sie sagen kein Wort, aber die ganze Welt versteht Sie!“ Worauf Chaplin erwidert haben soll: „Stimmt. Aber Ihre Kunst ist noch größer! Die ganze Welt bewundert Sie, auch wenn keiner ein Wort davon versteht, was Sie sagen.".

He continued to appear at La Scala through the 1929 season. In the spring and summer of 1929, Toscanini took the whole Scala company to Vienna and Berlin, where public, critics and professional musicians reacted with admiration to performances of six operas by Donizetti, Verdi, and Puccini. In Vienna they performed „Falstaff“ and „Lucia di Lammermoor“, in Berlin they performed „Falstaff“, „Il Trovatore“, Puccini’s „Manon Lescaut“, „Aida“ at the Staatsoper. At the Städtische Oper Unter den Linden they performed „Rigoletto“, „Lucia di Lammermoor“, which was partly radio broadcasted. Arturo Toscanini was strongly opposed to German and Italian fascism and left Europe for the United States in the mid-1930s. Albert Einstein left Germany for the United States in 1933. Einstein would later release a statement about Toscanini on the presentation of the American Hebrew Medal to him in 1938: “Only one who devotes himself to a cause with his whole strength and soul can be a true master. For this reason, mastery demands the whole person. Toscanini demonstrates this in every manifestation of his life.” In December 1930, Albert Einstein and Arturo Toscanini met backstage in New York, an article of the New York Times reports: “CERTAIN RELATIVITIES | Einstein and Toscanini Meet Backstage and Afford Demonstrations of Famous Theory | IT will be one week ago this afternoon that Albert Einstein listened to Arturo Toscanini's performance of Beethoven's "Pas total" symphony in the Metropolitan Opera House, applauded that performance warmly, then hastened backstage to talk with a master mind of music about the art that both men love. Mr. Einstein had reason to applaud, especial reason, since nothing illustrated more triumphantly than Toscanini’s performance the fundamental principle of the theory of relativity and its applicability to art as well as physics. Relativity in the realm of physics is, of course, one thing; relativity in the domain of art another. But in both fields a basic principle obtains, which destroys the possibility of fixed standards of measurement and teaches us that the universe itself is a thing of relative and not absolute, irrefragable values. The reviews of the Toscanini interpretation of the “Pastoral” symphony offered a good case in point. All the reviews were emphatic of the superlative qualities of the performance. The only question on which certain reviewers expressed differences of opinion was whether Toscanini’s superlative treatment of the symphony coincided precisely with the thought of Beethoven. [...]” The scientist repeatedly praised the musician, also in personal letters, for his attitude towards the Nazis and his support for Jews. In 1936 he wrote to the “Verehrten Maestro!”: “You are not just an unparalleled interpreter of universal musical literature […] You have also proven that you are a man of great dignity in the fight against the fascist criminals [...] The fact that a contemporary like you exists dispels many of the disappointments that on is continually subjected to [...]” With the help both of Einstein and Toscanini, celebrated Polish violinist Bronisław Huberman (1882-1947) saved some of the world's greatest musicians from the Nazis. They managed to help almost 1,000 musicians escape to Palestine. Together with them, he founded the Palestine Symphony Orchestra, which today enjoys worldwide fame as the Israel Philharmonic Orchestra. Acquired from a German private collection..

In fine condition, with a light central vertical fold, and soiling and handling wear to the covers. Accompanied by a letter of authentication from Viennese Antiquarian Book Dealer Ingo Nebehay, 1982. First edition of this extremely rare offprint, a remarkable association copy. The present paper was the crucial step between Einstein’s Entwurf theory of 1913 and the final form of general relativity which Einstein completed in November 1915: it develops the mathematical techniques necessary for the final formulation, namely the ‘absolute differential calculus’ of Tullio Levi-Civita, as well as the expression of the field equations in terms of a variational principle, which later proved to be of great importance. This author’s presentation offprint, with "Überreicht vom Verfasser" printed on upper wrapper, must not to be confused with the much more common trade offprint which lacks this printed statement (see below). We have located only one copy of this author’s presentation offprint at auction, in the collection belonging to Einstein’s son Hans Albert sold at Christie’s in 2006 (there was no copy in Einstein’s own collection of his offprints sold by Christie’s in 2008). "In summer 1914, Einstein felt that the new theory should be presented in a comprehensive review. He also felt that a mathematical derivation of the field equations that would determine them uniquely was still missing. Both tasks are addressed in a long paper, presented in October 1914 to the Prussian Academy for publication in its Sitzungsberichte. It is entitled ‘The formal foundation of the general theory of relativity’; here, for the first time, Einstein gave the new theory of relativity the epithet ‘general’ in lieu of the more cautious 'generalized' that he had used for the Entwurf" (Landmark Writings in Western Mathematics 1640-1940). "In the year that he was called to Berlin, on October 29, 1914, Einstein was able to present his work "Die formale Grundlage der allgemeinen Relativitätstheorie"…The "formal foundation" of the general theory of relativity was the tensor calculus. Without the tensor calculus, the general theory of relativity could not have been formulated…By October 1914, Einstein was finally able to present his results in mathematical form, and indeed in a manner that became the basis of his general theory of relativity of 1916. He introduced general covariants, contravariants, and also—what was new—mixed tensors, in order to represent the individual arithmetic operations, above all, the various types of multiplication. Thus the mathematical calculus necessary for the general theory of relativity was at the ready in 1914" (Reich). "The principal novelty [in the present paper] lies in the mathematical formulation of the theory. Drawing on earlier work with [Marcel] Grossman, Einstein formulated his gravitational field equations using a variation principle" (Calaprice, 47). The first important stage in the development of Einstein’s theory of gravitation was accomplished, with his friend and classmate the mathematician Marcel Grossmann, in their 1913 work Entwurf einer verallgemeinerten Relativitätstheorie und einer Theorie der Gravitation. "In this book, Einstein and Grossman investigated curved space and curved time as they relate to a theory of gravity. They presented virtually all the elements of the general theory of relativity with the exception of one striking omission: gravitational field equations that were not generally covariant. Einstein soon reconciled himself to this lack of general covariance through the ‘hole argument,’ which sought to establish that generally covariant gravitational field equations would be physically uninteresting" (Calaprice 40). Einstein’s ‘hole argument’, he believed, implied that general covariance was incompatible with the requirement that the distribution of mass-energy should determine the gravitational field uniquely. He believed, therefore, that the field equations should only be valid in certain coordinate systems, which he called ‘adapted’, and that only coordinate transformations from one adapted system to another adapted system should be allowed – he called these ‘justified coordinate transformations’. "Einstein’s move to Berlin in April 1914 marked the end of his collaboration with Grossmann. Fortunately, by this time Einstein no longer seems to have needed Grossmann’s mathematical guidance. By October 1914, he had completed a lengthy summary article [offered here] on his new theory, whose form and detailed nature suggest that Einstein felt his theory had reached its final form. The article contained a review of the methods of tensor calculus used in the theory and, flexing his newfound mathematical muscles, Einstein could even promise to give new and simpler derivations of the basic laws of the ‘absolute differential calculus’. Of great importance was the fact that Einstein had taken the new mathematical techniques of his last paper with Grossmann, generalized them and found in them a quite new derivation of the field equations" (Norton, p. 293). This new derivation made use, for the first time in Einstein’s work on the theory of gravity, of an action principle (or variational principle). Einstein worked initially with an action that was an arbitrary function of the metric tensor and its first derivatives, and then showed that with a particular choice of the action he could recover the Entwurf field equations. He further believed that he had found a simple general covariance condition which forced the action to take the Entwurf form. "Einstein had good reason to be pleased with this result. For it seemed to show that his theory was not just a theory of gravitation, but a generalized theory of relativity, in so far as it was concerned with establishing the widest covariance possible in its equations. His original derivation of the field equations [in Entwurf] had been based squarely on considerations in gravitation theory…The new derivation, however, focused on covariance considerations. He had found a simple way of formulating field equations that would have exactly the maximum covariance allowed by the ‘hole argument’, and they led him almost directly to his original Entwurf field equations. As a result he could promise to "recover the equations of the gravitational field in a purely-covariant-theoretical way" and claim to "have arrived at quite definite field equations in a purely formal way, i.e., without directly drawing on our physical knowledge of gravitation"… "Einstein appears to have remained satisfied with the theory he developed in 1914 through the first half of 1915. In March, April and early May he defended the theory wholeheartedly in an intense correspondence with Levi-Cività, who challenged Einstein’s derivation of the covariance properties of his gravitation tensor. But it seems that by mid-July he was less certain…By mid-October Einstein’s points of dissatisfaction with his theory had grown in number and intensity. They soon culminated in some of the most agitated and strenuous works of his life, in which generally covariant field equations were discovered…Einstein’s work [in the present paper] had brought him both temporally and conceptually closer than ever before to a generally covariant theory…It is hard to imagine that Einstein was unprepared for the ease with which his formalism of 1914 could be applied to his final generally covariant theory" (Norton, pp. 296-303). After publishing the generally covariant theory in November 1915, Einstein gave a further treatment of the variational formulation (Hamiltonsches Prinzip und allgemeine Relativitätstheorie, Sitzungsberichte (1916), pp. 1111-1116). By this time, the great German mathematician David Hilbert had published his own account of general relativity in terms of a variational principle [Die Grundlagen der Physik (Erste Mitteilung), Nachrichten der Königliche Gesellschaft der Wissenschaften zu Göttingen. Mathematisch-physikalische Klasse, November 1915, 395-407]. This led to some controversy over who had been the first to publish the final version of general relativity (although Hilbert himself never claimed priority). "Hilbert, through his important paper of November 1915, is generally thought of as introducing the comprehensive use of these action principles to the theory. My analysis shows that although Einstein might have drawn some of his work of 1916 in this area from Hilbert’s, his basic mathematical apparatus and even the notation itself had its ancestry in his own work earlier in 1914 and 1915" (Norton, p. 303). This author’s presentation offprint is of extreme rarity, and must be distinguished from other so-called ‘offprints’ of papers from the Berlin Sitzungsberichte, many of which are commonly available on the market. The celebrated bookseller Ernst Weil (1919-1981), in the introduction to his Einstein bibliography, wrote: "I have often been asked about the number of those offprints. It seems to be certain that there were few before 1914. They were given only to the author, and mostly ‘Überreicht vom Verfasser’ (Presented by the Author) is printed on the wrapper. Later on, I have no doubt, many more offprints were made, and also sold as such, especially by the Berlin Academy." If the term ‘offprint’ means, as we believe it should, a separate printing of a journal article given (only) to the author for distribution to colleagues, then ‘offprints’ were not commercially available. Although there is certainly some truth in Weil’s remark, in our view it requires clarification and explanation. Until about 1916, most of Einstein’s papers were published in Annalen der Physik; from 1916 until he left Germany for the United States in 1933, most were published in the Berlin Sitzungsberichte. The Sitzungsberichte differed from other journals in which Einstein published in that it made separate printings of its papers commercially available. These separate printings have ‘Sonderabdruck’ printed on the front wrapper, the usual German term for offprint, but they are not offprints according to our definition. They were available to anyone; indeed a price list of these ‘trade offprints’ is printed on the rear wrapper. True author’s presentation offprints can be distinguished from these trade offprints by the presence of ‘Überreicht vom Verfasser’ on the front wrapper. In the period 1916 to 1919 or 1920, the Sitzungsberichte trade offprints are themselves rare: for example, ABPC/RBH list only three ‘offprints’ of Einstein’s famous 1917 Sitzungsberichte paper ‘Kosmologische Betrachtungen zur allgemeinen Relativitätstheorie’ (the auction records do not distinguish between trade and author’s presentation offprints). After 1919 or 1920, however, the trade offprints became much more common, although the author’s presentation offprints are still very rare. The reason for this change is that it was only in 1919 that Einstein became famous among the general public. It might seem obvious that Einstein’s fame dates from 1905, his ‘annus mirabilis’, in which he published his epoch-making papers on special relativity and the light quantum. However, these works did not make him immediately well known even in the physics community – many physicists did not understand or accept his work, and it was two or three years before his genius was fully accepted even by his colleagues. He secured his first academic position, at the University of Bern, in 1908. Among the general public, Einstein became well known only in late 1919, following the success of Eddington’s expedition to observe the bending of light by the Sun, which confirmed Einstein’s general theory of relativity. This was front-page news, and made Einstein universally famous. (See Chapter 16, ‘The suddenly famous Doctor Einstein’, in Pais, Subtle is the Lord, for an account of these events). Before 1919 the trade offprints of Einstein’s papers would probably only have been purchased by professional physicists; after 1919 everyone wanted a memento of the famous Dr. Einstein, whether or not they understood anything of theoretical physics, and the trade offprints of his papers were printed and sold in far greater numbers than before to meet the demand. It is telling that when these post-1919 trade offprints appear on the market, they are often in mint condition – they were never read simply because their owners were unable to understand them. Boni 65; Weil 68. Calaprice, The Einstein Almanac; Norton, ‘How Einstein Found His Field Equations: 1912-1915’, Historical Studies in the Physical Sciences 14 (1984), pp. 253-316; Norton, ‘Einstein and Nordström: some lesser-known thought experiments in gravitation,’ pp. 3-30 in The Attraction of Gravitation: New Studies in the History of General Relativity, edited by John Earman, Michel Janssen, John D. Norton, 1993; Reich, Einstein’s "Formal Foundations of the General Theory of Relativity" (1914) (http://mathineurope.eu/images/information_pic/hist_phil_pic/calendar_pic/2014einstein/Einstein_English.pdf). For the history of tensor calculus, including Einstein’s application of it to general relativity, see Reich, Die Entwicklung des Tensorkalküls, Birkhäuser 2012..

Ich illustriere durch einen Vergleich aus der gewöhnlichen Mechanik. Man kann das Koordinatensystem so wählen, dass in einem bestimmten Augenblick ein Körper, z.B. die Erde in Ruhe ist. Die Bewegung der Erde ist also bedingt durch die Wahl des Bewegungssystems des Koordinatensystems. Man kann aber das Koordinatensystem nicht so wählen, dass relativ zu ihm gleichzeitig sowohl Erde als Mond in Ruhe sind. Durch den Bewegungszustand des mechanischen Koordinatensystems können eben nur solche Bewegungen ,erzeugt’ werden, bei welcher alle Körper dieselbe Geschwindigkeit und Bewegungsrichtung haben. Diese Analogie dürfte den Sachverhalt genügend aufklären. […]“.

1919 gründete er mit einem Stiftungskapital von 1 Million Mark die Stiftung für Physik, Chemie und Naturwissenschaften. Der Universität München machte er umfangreiche Schenkungen. 1922 erwarb er das Schloss Lautrach in Lautrach (Oberschwaben), ließ es renovieren und stellte es dann als Erholungsheim für Professoren und Studenten zur Verfügung. Er hielt hier mit von ihm ausgewählten Wissenschaftlern sogenannte „Fakultätssitzungen“ ab, so etwa mit Karl von Frisch, Wilhelm Wien, Richard Willstätter, Albrecht Kossel, Arnold Sommerfeld und Albert Einstein. (Wikipedia-Abfrage v. 14.6.2023).

Written below by a different hand is the English translation as it was finally published: "while it leads to a well-defined theory of the gravitational field it does not determine sufficently the theory of the total field (which includes the electromagnetic field). The reason for this is the fact that the general field laws are not sufficently determined by the general principle of relativity alone". - An exceedingly fine autograph, wherein Einstein implicitly states why he spent so many of his final years searching for a Unified Field Theory. Written on the address side of an envelope addressed to him. Slight damage to edges, somewhat wrinkled..

- Popper-Lynkeus was a wide-ranging thinker in both the scientific and social spheres: one of his most notable ideas was the proposition of a new social system in which all individuals are provided with goods of primary necessity..

Hoffentlich sehen wir uns dort wieder einmal gemütlich [...]". - In an earlier letter of Elsa's, also regarding family investments administered by Kuno (undated but written aboard the "Oakland", probably in the port of Bremen on 10 December 1932, about to depart for a winter cruise to Pasadena via Middle America), Einstein adds a poignant note about his younger son Eduard, who suffered from schizophrenia and had recently been committed to a mental asylum in Switzerland: "Nimm bitte diese schleichende Sorge von uns; das Leben hat in letzter Zeit Schweres gebracht, da mein liebster Sohn, der Jüngere, in einer Anstalt hat untergebracht werden müssen (Geisteskrankheit) [...]". - In the final missive, possibly another postscript torn from a longer letter, Einstein gives his consent in a single word ("Einverstanden"), signing and dating: "Princeton, 9. Mai 1934 / Albert Einstein". Elsa's own letters discuss travel, finances, Albert Einstein's stay in Spa, etc. - Each sheet with marginal binder holes affecting a few letters, otherwise flawless..

The two men were by this time watching the collapse of Nazism and hoping that a new peaceful German leadership would emerge from the ashes of war, although Einstein here expresses his fear for the future of Europe. Held appears to have sent Einstein a copy of the latest Upton Sinclair novel, "Dragon Harvest" (1945), which was set during the period between the Munich Crisis and the Fall of Paris. It is not clear if Held had realised that Einstein and Sinclair knew each other; Einstein had contributed a preface to Sinclair's "Mental Radio" (1930), and Sinclair made Einstein a friend of his fictional hero Lanny Budd, an American socialist. - On stationery with blindstamped letterhead. Slightly spotty and wrinkled..

I intend once more to encourage Mr. Plesch to put everything in order. As regards your inventions, I suggest that you send them for evaluation to my friend Professor Karman at the California Institute of Technology, who is a first-class expert and has influential connections to the realm of construction and practical implementation in the field. I enclose a letter to him [...]" (transl.). - Wsevolode Grünberg was the nephew of the Russian orthodontist and collector Josef Grünberg, a close friend of both Albert Einstein, who gave him the nickname "Bolshie", and János Plesch during their time in Berlin. It appears that Einstein and his second wife Elsa had become acquainted with Wsevolode Grünberg shortly before their friend's death in 1932. Travelling to America in 1939, Grünberg approached Einstein for an introduction to fellow engineers in the U.S. and help with his inheritance issue back in Europe. The two men met in June 1939 at the home of Irving Lehman in Port Chester, New York, and Einstein subsequently did what he could for Grünberg. In the early 1940s, Grünberg's important hydrofoil designs were used by the National Advisory Committee for Aeronautics (NACA) to build a seaplane model that was successfully tested at Langley, VA. Ironically, the classification of the project prevented the French citizen Grünberg from seeing the results of the tests until years after the war. Grünberg later became a U.S. citizen, changing his name to Waldemar A. Craig. - Traces of folds. On Einstein's embossed Princeton stationery..

In 1949, having left his position with Einstein at Princeton University, he published "Some Results in Einstein's Unified Field Theory". The two scientists remained in a working relationship afterwards. - On headed paper; perfectly preserved..

I would appreciate it greatly if you would renew the passports, especially as my daughter is the student of a Belgian sculptor at Bruges" (transl.). - Apparently, the letter was not sent directly to Costermann but was forwarded by the escape agent Max Gottschalk. His letter to the "Director General" is dated 7 May 1934 and accompanied Einstein's letter from 23 April with a further plea to treat the request favourably without delay. - Elsa Einstein's letter from 22 May 1933 to a "Director", very likely the same Costermann, concerns the original foreigner's passport for Margot. Elsa announces that Margot will arrive in Brussels the following day and contact the recipient directly. - Albert and Elsa Einstein were in the U.S. when the Nazis seized power in Germany in February 1933. As they could not return to their home in Potsdam, they sailed to Antwerp in March 1933, immediately renounced their German citizenships, and rented a small villa in Le-Coq-sur-Mer (De Haan) near Bruges, where Margot and her husband joined them. As early as September 1933, Albert and his wife emigrated to the U.S.; Margot and Dimitri would follow them in 1934 after the death of Margot's elder sister Ilse Einstein from tuberculosis. - Following the early death of her mother in 1936, Margot Einstein stayed with her father-in-law in Princeton, studied sculpture, and would live in the family home until her own death in 1986. Little is known about her marriage to Dimitri Marianoff. The couple had married in Berlin on 29 November 1930, much to the displeasure of Albert and Elsa, who distrusted their son-in-law; indeed, Marianoff turned out to be a Russian spy. The marriage probably ended soon after their arrival in the U.S. Marianoff profited from his previous close relationship to the world's most famous physicist by publishing a memoir "Einstein. An Intimate Study of a Great Man" in 1944. - On stationery with typed letterhead of Einstein's first address in Princeton: "2, Library Place". With an official note "Passeport Etr." in ink and a contemporary pencil translation into French. Minimally creased, two minor tears to the left margin and one to the lower margin. - The letter by Elsa Einstein shows three tears and staple holes. The letter by Gottschalk bears an official note "M. Marianoff et Gottschalk le 8.5.34" in ink and "T.U." (possibly "tâche urgent") in crayon and a minor tear..

Man muss den Mut haben, die Dinge in ihrer Nackheit zu sehen und zu verstehen, um ein ganzer Mensch sein zu können. Spinoza hat gezeigt, dass man dies vollbringen kann. Es müsste Einer kommen, der ihn in schlichter, einfache Sprache neu erstehen liesse. Vielleicht sin Sie der Mann. […]“ Im Brief von 1950: „[…] Sie haben die Unterscheidung zwischen der ethischen Tat bezw. Zielsetzung einerseits und dem Gefühlsmotiv, das zur Tat bezw. Wertung führt andererseits, hübsch ausgeführt. Der Gedanke selbst ist natürlich nicht neu. So ist z.B. Kand drolligerweise so weit in der objectiven Auffassung des Ethischen gegangen, dass er eine Tat nicht als ethisch wertvoll anerkennt, wenn sie unmittelbar einem elementaren Gefühl (z.B. Mitleid) entspringt; er lässt als legitime gefühlsmässige Basis des Ethischen nur das Pflichtbewusstsein gelten, worüber sich schon Schiller lustig gemacht hat. Nach meiner Meinung ist die objective Auffassung, die dem Gegenstand der Ethik angemessens. Die ethische Tat veranlassende emotionelle Situation gehört eigentlich nicht zur Ethik sondern zu Psychologie. […]“.