Sefer Yetzirah (Hebrew: ספר יצירה‎ Sēpher Yəṣîrâh, Book of Formation, or Book of Creation) is the title of the earliest extant book on Jewish mysticism, 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 have not reached consensus on the question of its origins. According to Rabbi Saadia Gaon, the objective of the book's author was to convey in writing how the things of our universe came into existence.