This is the only book that focuses on the political aspects of Albert Einstein and his work as viewed by various national authorities between the two world wars, contributing much toward a better understanding of Einstein's decisive break with Germany. In particular, the author carefully scrutinizes Einstein's FBI file from 1950-55 against material from European investigative files, and presents hitherto unknown documentation on Einstein's alleged contacts with the German Communist Party and the Comintern. Grundmann's study of Einstein's participation on a committee of the League of Nations, based on archival research in Geneva, is also new.