The Sefer Yetzirah, considered the oldest book on kabbalistic philosophy, is translated as the Book of Formation or Book of Creation or Book of Tradition. It was first put into writing possibly around 200 ce, although this is a matter of much dispute. Jewish traditional scholars propose that the patriarchs (Abraham, Isaac, and Jacob) wrote the Sefer Yetzirah, but there is no actual documentary evidence to support that view, and the book always attracts debate about its date of origin and its authorship. Despite the title, the text is not an alternate version of Genesis or even a story about Creation itself. Rather, it presents a mystical, esoteric version of the origin of the universe and humanity, and thus it is a key document in the history of Jewish mysticism. Unlike other kabbalistic writings, the Sefer Yetzirah is written in Hebrew and not Aramaic. It exists in more manuscripts than any other Hebrew work except the Torah itself. There are four “families,” or versions, of the Sefer Yetzirah: the Short Version, the Saadia Version, the Gra Version, and the Long Version; the translation reproduced here is based on the Saadia Version. All the variants are quite similar in content, with the differences being in structure, order, and length; the work is usually presented as thirty-three paragraphs within six chapters, although older versions will include a chapter at the end called “The Letters of our Father Abraham.”