Originally published in Tzvi M. Rabinowicz (ed.), The encyclopedia of Hasidism (1996), p. 275. A halakhic authority of universal recognition, Landau was a determined opponent of Hasidism, considering the claim made for the hasidic tzaddik as a “seer” (ro’eh) gifted with prophetic powers to be a serious departure from the rabbinic norm. His particular opposition was…