The Collected Papers of Albert Einstein, Volume 3 presents Einstein’s writings for the two-year period starting in October 1909. The initial date marks Einstein’s departure from the Swiss Patent Office at Bern, which had been his professional home for seven years, and the beginning of his first academic appointment, at the University of Zurich. The volume concludes with the masterful report that Einstein, by then a full professor at the German-language university in Prague, gave to the original Solvay Congress, the first international meeting devoted to the problems of radiation and the quantum theory. Most of Einstein’s efforts during these years went into his struggle with these ever more perplexing problems of quanta, on which he made discouragingly little progress.