Hermann Cohen's Religion of Reason, Out of the Sources of Judaism (first pub. 1919) is widely taken to be the greatest work in Jewish philosophy and religious thought since Maimonides' Guide to the Perplexed. It is at once a Jewish book and a philosophical one: Jewish because it takes its material from the literary tradition that extends from the Bible to the rabbis to the great medieval philosophers; philosophical, because it studies that material in order to construct a worldview that is rational in the broadest sense of the term. This edition is designed for classroom use. It reprints a 1972 introduction by Leo Strauss and includes an essay on the work by Steven Schwarzschild. A new introduction by Kenneth R. Seeskin situates Cohen's masterwork in the history of modern philosophical and religious thought.