For more than one hundred fifty years the biography of the putative founder of Hasidism, Israel ben Eliezer, the Ba'al Shem Tov, has been on the agenda of Jewish studies and, indeed, the history of religion. Hasidism has had a tremendous impact in both the spiritual and social realms. In Hasidism the mystical ethos became part of everyday religion; Kabbalah was turned into a tool for intensifying communal life, rather than for encouraging isolation; emphasis was placed on the need to relate to God through joy, instead of abnegation; and addressing the individual's needs became a major religious objective. In short, Hasidism created a unique sort of pietism that captured the imagination of the masses of eastern European Jewry in the nineteenth and early twentieth centuries. After a period of decline, marked especially by the tragic fate of virtually all Hasidic communities during the Holocaust, Hasidism has proven it has the power to flourish in modern democratic societies. Today we are witnessing tremendous growth of Hasidic groups in Israel, America, and Europe.

Socially, the Hasidim, devoted to their charismatic leaders (zaddikitn or rebbes), found a means of organization that successfully bridged many of the gaps between the elite and the rank and file. They formed disciplined, yet entirely voluntary, communities where the interconnectedness of members’ souls was manifest. Issues of social justice and economic welfare were as central to the zaddik's concern as were prayer and ritual observance. In our own time, the moral and religious teachings of famous zaddikim and the Hasidic style of worship with its singing and dancing inform, to some degree, the ideology and practice of all streams of Jewish religion and exert an influence on certain non-Jewish circles as well. Moreover, the Hasid in his caftan and fur-trimmed hat, fervently at prayer, has been adopted the world over as a stereotypical emblem of traditional Jewish life.

As the progenitor of this movement that has been so central to the development of modern Judaism, the Besht (the common Hebrew acronym of Ba'al Shem Tov, employed by Israel himself) arouses keen interest. There is a tacit assumption among researchers that to understand the Besht is somehow to understand Hasidism, and with it much of modern Jewish religion and experience.