"Assaf is a scholar who knows how to manage vast bits of detail but also how to fit them together in a coherent and plausible whole. . . . [He] has used the only possible method for sifting among sources, that of common sense. He has done so with great success and produced a first-rate biography."–AJS Review "This is a path-breaking and thorough study of an important and neglected chapter of modern Jewish history."American Historical Review "It is a very important addition to the history of Hasidism and the study of East European Jewish history."—Religious Studies Review