Jewish Mysticism; basic book is the “Zohar,” written by Rabbi Shimon bar Yochai in the Second Century, CE, while in hiding from the Romans. He was recording an ancient tradition, much less known because of its esoteric nature. Despite this aspect, it is understandable, and meaningful, apparently, for average Jews who delve into it, as its popularity in Chassidut demonstrates. On the other hand, on its deepest levels, it is somewhat dangerous, as we see from the account of the four great scholars who “entered the PARDES,” from which only one; namely, Rabbi Akiva, emerged whole in mind and soul. “PARDES” is an acronym, representing the four basic branches of Torah knowledge, the “S” corresponding to “Sod,” Secret, as “Torat HaSod,” the Secret Torah, is another name for Kabbalah.
