Yaakov Emden (1697–1776), himself an Orthodox Kabbalist who venerated the Zohar, concerned to battle Sabbatean misuse of Kabbalah, wrote the "Mitpaḥath Sfarim" ("Veil of the Books"), an astute critique of the Zohar in which he concludes that certain parts of the Zohar contain heretical teaching and therefore could not have been written by Shimon bar Yochai. He also expressed the extremely unconventional view, contrary to all evidence, that the pious Maimonides could not have written the "Guide of the Perplexed", which must have been the work of an unknown heretic.