I N T R O D U C T I O N T O V O L U M E 1 6 l x x x i plan, while informing him that he himself did not wish to join the new board (Doc. 339). Hilbert was delighted with the outcome, especially since he no longer wanted to be encumbered by associate editors. Beginning in 1929, Mathematische Annalen would have only three editors: Hilbert, Blumenthal, and Erich Hecke. Brouwer tried to regroup, but not until the mid-1930s was he able to found a new journal, Compositio Mathematica. In striking contrast with Hilbert’s restructuring of the Annalen, Brouwer launched this new undertaking with a large international advisory board, one of whose members was Bieberbach, his principal ally. The lat- ter soon resigned, however, to avoid any association with the Jewish members on the board. Six years after its founding, Compositio ceased publication following Germany’s occupation of the Netherlands. IX. Popularization Efforts At the end of his trip to South America in 1925, Einstein reported in letters home that he had grown weary of giving popular lectures on his theories. More than once he vowed never to go on another such trip in which his public appearances were crowded so closely together, remarking to his wife Elsa that it was “one big drudgery” (Vol 14, Doc. 471) and “such a hard slog” (Vol. 14, Doc. 477). However, he retained his commitment to what we would now call scientific outreach, in spite of privately entertaining reservations about the value of popularization. When, in later years, he was asked by a biographer of Eddington, perhaps the best-known popularizer of relativity, for his views on Eddington’s talents in educating the pub- lic, he slyly replied that a scientist should not attempt to popularize his theories if he does “he is a fakir—it is the duty of a scientist to remain obscure” (Douglas 1956, pp. 99–100). By remarks such as these, Einstein lent some credence to the view that he was a classic example of the (natural) philosopher in the ivory tower. After all, his ideas are popularly believed to be too complex and esoteric to be understood by any but a literal handful of brilliant individuals. But as has been observed by Einstein scholars (Gutfreund and Renn 2015), in spite of Einstein’s qualms about the efficacy of popularization, this image is at odds with his ready willingness to pres- ent ideas in qualitative terms for nonscientific audiences. He repeatedly acceded to requests to engage with popular audiences, especially in essay form. Doc. 420, written for a young-people’s magazine, is an obvious case in point. In this volume we find him providing introductions to relativity in popular mag- azines and newspapers, giving nontechnical lectures to audiences of different kinds, and discussing his physics in qualitative terms in private correspondence. In addition to the excitement surrounding his latest work on unified field theory, many