Hasidism is a Kabbalah-inspired Jewish spiritual revival that centers on charismatic leaders and miracle workers known as "Zaddikim." By the beginning of the 19th century, Zaddikim and their devotees had forged Hasidism into a movement of such power and scop that it had dramatically altered the spiritual, cultural, and social timbre of Jewish communities across Eastern and East Central Europe. Glenn Dynner provides a first critical look at Hasidism's stunning transformation into a mass movement by highlighting the variegated region of Central Poland. His research shatters prevailing romantic notions about Hasidism during its meteoric rise, revealing Polish Zaddikim as shrewd populists who cultivated folksy images and achieved immense grassroots appeal, and yet proved equally adept at securing elite support, neutralizing powerful opponents, and seizing control of Jewish communal institutions across Central Poland.