Hasidism, a controversial, mystical-religious movement of Eastern European origin, has posed a serious challenge to mainstream Judaism from its earliest beginnings in the middle of the eighteenth century. Decimated by the Holocaust, it has risen like a phoenix from the ashes and has reconstituted itself as a major force in the world of ultra-Orthodox Judaism. Philosopher Martin Buber found inspiration in its original tenets and devoted much of his career to making its insights known to a wide readership.