Originally, in the Talmud, the books of the Bible other than the Pentateuch. Gradually after around 1200 the term became applied to the oral tradition supposedly handed down from Moses to the Rabbis of the Mishnah and the Talmud; it accumulated aspects of cosmology, angelology, magic, and gnosticism, becoming a mystical and esoteric tradition of interpretation of the books of the Old Testament. A specialist in this study is called a kabbalist. Like astrology, it is a magnet for the weak-minded.