Sefer Yetzirah or Book of Creation is the title of the earliest extant book on Jewish esotericism, although some early commentators treated it as a treatise on mathematical and linguistic theory as opposed to Kabbalah. Yetzirah is more literally translated as "Formation"; the word Briah is used for "Creation".The book is traditionally ascribed to the patriarch Abraham, although others attribute its writing to Rabbi Akiva. Modern scholars haven't reached...