From Inner.org, the writings of Rabbi Ginsburgh (hassidic kabbalist in Israel), from his weekly mailing list (available to all, click here):
"In general there are 5 stages in the revelation of the wisdom of Kabbalah, each stage appearing (one might say, even encoded) within a particular text."
Two: The Zohar (the Book of Brilliance)
Unlike The Book of Formation, the Zohar, the text revealing the second stage of Kabbalah, is a very large one. Its content is primarily structured as an interpretation of the Bible in general and the Five Books of Moses, in particular. The Zohar, though it speaks in a usually less enigmatic language than the Book of Formation, is structurally varied. Some of the content appears as story-telling, some of it as an in-depth analysis of “higher worlds,” the reality of sefirot, the way in which the sefirot develop into “figures” (partzufim) spiritual personas of the higher worlds, and so on. There are some parts of the Zohar (like the Idra Rabbah and Idra Zuta), which remained almost completely incomprehensible until the Arizal (16th century CE) shed light shed on them (more on the Arizal in the fourth stage). In the complete corpus of the many writings that make up the Torah, the Zohar is considered a midrash—a homiletic or hermeneutic discourse on the Torah. Sometimes the Zohar is even referred to as Midrash Rashbi, Rashbi being the acronym of its author’s name: Rabbi Shimon bar Yochai.
Though originally composed by Rabbi Shimon bar Yochai in the 2nd century CE, the Zohar was not openly published for another 1200 years. During the interim, it was passed from mentor to disciple. “A thing in its [proper] time is good,”and such was the public revelation of the Zohar. Immediately upon its revelation, the Zohar spread throughout the Jewish world of learning, and many of the Kabbalistic scholars began to try to unlock its secrets, by properly interpreting its myriad of allusions and metaphors. This went on for almost 200 years, until this process reached its zenith with the work of Rabbi Moshe Cordovero (1522-1570), known by his acronym, the Ramak.
BS"D - בסיעתא דשמיא