"The Einstein Almanac" takes a look at Einstein's year-by-year output, explaining his 300 most important publications and setting them into the context of his life, science, and world history.

A translation of selected non-English texts included in Volume 13 is available in paperback. Since this supplementary paperback includes only select portions of Volume 13, it is not recommended for purchase without the main volume. Every document in The Collected Papers of Albert Einstein appears in the language in which it was written, and this supplementary paperback volume presents the English translations of select portions of non-English materials in Volume 13. This translation does not include notes or annotation of the documentary volume and is not intended for use without the original language documentary edition which provides the extensive editorial commentary necessary for a full historical and scientific understanding of the documents.

This volume covers one of the most thrilling two-year periods in twentieth-century physics, as matrix mechanics—developed chiefly by W. Heisenberg, M. Born, and P. Jordan—and wave mechanics—developed by E. Schrödinger—supplanted the earlier quantum theory. The almost one hundred writings by Einstein, of which a third have never been published, and the more than thirteen hundred letters show Einstein’s immense productivity and hectic pace of life. Einstein quickly grasps the conceptual peculiarities involved in the new quantum mechanics, such as the difference between Schrödinger’s wave function and a field defined in spacetime, or the emerging statistical interpretation of both matrix and wave mechanics. Inspired by correspondence with G. Y. Rainich, he investigates with Jakob Grommer the problem of motion in general relativity, hoping for a hint at a new avenue to unified field theory. Einstein falls victim to scientific fraud when, in a collaboration with E. Rupp, he becomes convinced that the latter’s experiments, aimed at deciding whether excited atoms emit light instantaneously (in quanta) or in a finite time (in waves), confirm a wave-theoretic explanation. While it was known that the teenage Einstein had been romantically involved with Marie Winteler in 1895, newly discovered documents reveal that his love for Marie was rekindled in 1909–10 while he was still married to Mileva Marić. The 1925 Locarno Treaties renew Einstein’s optimism in European reconciliation. He backs the “International manifesto against compulsory military service” and continues his participation in the League of Nations’ International Committee on Intellectual Cooperation. He remains intensely committed to the shaping of the Hebrew University in Jerusalem, although his enthusiasm for this cause is sorely tested.

The more than one thousand letters and several dozen writings included in this volume cover the years immediately before the final formulation of new quantum mechanics. The discovery of the Compton effect in 1923 vindicates Einstein's light quantum hypothesis. Niels Bohr still criticizes Einstein’s conception of light quanta and advances an alternative theory, but Walther Bothe and Hans Geiger perform a difficult experiment that decides in favor of Einstein’s theory. At the same time, Satyendranath Bose sends a new quantum theoretical derivation of Planck’s law to Einstein and he discovers what is now known as Bose-Einstein condensation. Einstein attempts to reformulate a unified theory of the gravitational and electromagnetic fields. In early November 1923, Einstein flees overnight to the Netherlands in the wake of threats on his life and anti-Semitic rioting in Berlin. He rejoins the International Committee on Intellectual Cooperation in June 1924, and supports the idea of a European union. He joins the board of governors of Hebrew University, which opens in April 1925, and celebrates the event in Buenos Aires while on a seven-week lecture tour of Argentina, Uruguay, and Brazil. During this period, he delivers lectures, meets with heads of state, visits major institutions, and attends receptions hosted by the local Jewish and German communities. He has a serious, but short-lived, falling out with his son Hans Albert and his first wife Mileva Maric-Einstein over how to invest part of the Nobel Prize money and he rescues his sister Maja and her husband from debt on their house. Einstein has a fourteen-month romantic relationship with his secretary, Betty Neumann, which he ends in October 1924.