Rabbi Yisroel Salanter, founder of the mussar movement, wrote no seforim himself, but his main disciple, Rabbi Yitzchok Blazer, preserved his rebbe's legacy with his classic work, Ohr Yisroel. Exposing the character flaws of Jews individually and societally, the mussar movement incited vehement controversy in its day, only to conquer the yeshiva world in later years. Rabbi Wein melds together a biography of Rabbi Yisroel Salanter with the history of the movement he inspired, giving a glimpse into a little-known but highly influential sefer.