Zohar

Basic Book of Jewish Mysticism; written by Rabbi Shimon ben Yochai in the Galilean Cave, during his period of enforced hiding from the Romans. Bar Yochai was a disciple of Rabbi Akiva, and was the recipient of a living tradition of Kabbalah from his master, but he is the one who recorded it for posterity in this work, whose name means “The Splendor,” or “The Brilliance.”

Taken from: http://www.ou.org/about/judaism/yz.htm#zohar