Jan Karski was the wartime emissary of the Polish underground which first reported to President Roosevelt on the massacre of the Jews in Poland. Since 1952 he has been at the Foreign Service School at Georgetown, where he is a professor of government. His book, produced after many years of research, is a truly remarkable work. It not only provides the first comprehensive diplomatic history of Poland and the Great Powers, but it is well written, enriched by informative anecdotes and new material from recently opened archives.