Book excerpt: The author provides the first comprehensive critical edition of a text which was a fundamental influence on Jewish thought in the medieval period and has continued to fascinate scholars and students of Judaism to the present day. With its English translation of the three earliest recensions and its commentary on the variant early texts of the work, this book is essential reading for anyone interested in the growth and emergence of the Jewish mystical movement. Contents include: The fluid state of the text of Sefer Yesira, Why a new edition of Sefer Yesira?, The "original text" of SY or "the earliest recoverable text"?, Editing Jewish texts from the first millennium C.E., The Manuscripts, The rules of the edition, Abbreviations in the textual apparatus, Notes on the manuscripts, The chapter and paragraph divisions (Appendix II), the Four Pre-Kabbalistic commentaries, The Earliest Recoverable Text of Sefer Yesira and the Three Recensions, The Three Recensions of the SY Text Tradition.