The Zohar (Hebrew: זֹהַר, lit Splendor or Radiance) is the foundational work in the literature of Jewish mystical thought known as Kabbalah. It is a group of books including commentary on the mystical aspects of the Torah (the five books of Moses) and scriptural interpretations as well as material on Mysticism, mythical cosmogony, and mystical psychology. The Zohar contains a discussion of the nature of God, the origin and structure of the universe, the nature of souls, redemption, the relationship of Ego to Darkness and "true self" to "The Light of God," and the relationship between the "universal energy" and man. Its scriptural exegesis can be considered an esoteric form of the Rabbinic literature known as Midrash, which elaborates on the Torah.
The Zohar is mostly written in what has been described as an exalted, eccentric style of Aramaic, which was the day-to-day language of Israel in the Second Temple period (539 BCE – 70 CE), was the original language of large sections of the biblical books of Daniel and Ezra, and is the main language of the Talmud.
The Zohar first appeared in Spain in the 13th century, and was published by a Jewish writer named Moses de Leon. De Leon ascribed the work to Shimon bar Yochai, a rabbi of the 2nd century during the Roman persecution who, according to Jewish legend, hid in a cave for thirteen years studying the Torah and was inspired by the Prophet Elijah to write the Zohar. This accords with the traditional claim by adherents that Kabbalah is the concealed part of the Oral Torah.
While the traditional majority view in religious Judaism has been that the teachings of Kabbalah were revealed by God to Biblical figures such as Abraham and Moses and were then transmitted orally from the Biblical era until its redaction by Shimon ben Yochai, modern academic analysis of the Zohar, such as that by the 20th century religious historian Gershom Scholem, has theorized that De Leon was the actual author. The view of non-Orthodox Jewish denominations generally conforms to this latter view, and as such, most non-Orthodox Jews have long viewed the Zohar as pseudepigraphy and apocrypha while sometimes accepting that its contents may have meaning for modern Judaism. Jewish prayerbooks edited by non-Orthodox Jews may therefore contain excerpts from the Zohar and other kabbalistic works, even if the editors do not literally believe that they are oral traditions from the time of Moses.
There are people of religions besides Judaism, or even those without religious affiliation, who delve in the Zohar out of curiosity, or as a technology for people who are seeking meaningful and practical answers about the meaning of their lives, the purpose of creation and existence and their relationships with the laws of nature, and so forth; however from the perspective of traditional, rabbinic Judaism, and by the Zohar's own statements, the purpose of the Zohar is to help the Jewish people through and out of the Exile and to infuse the Torah and mitzvot (Judaic commandments) with the wisdom of Kabbalah for its Jewish readers.
Read more about Zohar: Etymology, Contents, Commentaries, Zohar Study (Jewish View), English Translations