The Zohar, also known as Sefer ha-Zohar, or “The Book of Radiance,” is now the primary text for students of Kabbalah. The beginnings of the Zohar first appeared around 1280 C. E., when a Spanish mystic named Moses de Leon began circulating small booklets written in Aramaic, a long defunct language. De Leon claimed that the booklets were taken from ancient texts written by the great second-century rabbi Simeon ben Yohai.

Rabbi Yohai, fleeing persecution by the Romans in Palestine, hid in a cave for thirteen years with his son, Eliezar. The Jewish prophet Elijah supposedly visited Yohai and his son in the cave, after which God inspired Yohai to write down the wisdom he gathered from Elijah’s teachings. De Leon claimed his pamphlets contained Yohai’s writing. Most kabbalists believed de Leon’s story for hundreds of years, though others have since expressed doubt and think de Leon wrote the pamphlets himself. Even though De Leon is now widely credited with authoring the work, the Zohar is still considered a triumph of poetic writing and mystical thought.

The Zohar is written in a very unconventional style, which some associate with the technique of “automatic writing.” Automatic writing requires the writer to enter a mystical trance and then immediately transcribe whatever thoughts first come to mind, no matter how scattered or unrelated. Automatic writing could supposedly unveil ideas buried deep in one’s consciousness, and perhaps bring a writer closer to understanding God. Others contend that the Zohar’s bizarre style results not from the automatic writing of one person, but from the contributions of various authors over hundreds of years.

The Zohar describes the journey of Rabbi Simeon ben Yohai and ten companions through Galilee, the northern region of Palestine and, formerly, the kingdom of Israel. Along their journey, the travelers discuss their interpretations of the Torah, and specifically the Torah’s main characters. The characters become a part of the narrative of the Zohar, their lives weaving in and out of those of Yohai and his group. The companions come and go fluidly within their own group—they often turn from one character into another.

The Zohar uses the term “Ein Sof,” meaning “the infinite,” for God. Ein Sof is a departure from the traditional concept of divinity, which portrays God as a knowable presence, a being in the heavens that people can comprehend and feel. Ein Sof, on the contrary, is so vast that it’s unknowable, beyond the boundaries of human comprehension. Kabbalists believe that at most they can know merely fragments of Ein Sof, which they receive only through profound mystical experiences.

Though the Zohar and its teachings spread quickly from Spain and Italy into other parts of Western Europe, it was slow to reach Eastern Europe—at least at first. After the expulsion of the Jews from Spain in 1492, study of the Zohar became more widespread as Jews fled eastward. The Zohar’s popularity reached its peak in the sixteenth and seventeenth centuries. The Zohar remains in print today and has been translated into English in a twenty-two-volume set.