Both the date of the writing and the name of the author or authors of the Seyfer Yetzirah or Book Of Formation are unknown. And with respect to its authorship, it is most likely that the details will never be completely known. Admittedly, in the last section of the book its is stated that Abraham, "our father", was the author; but this is undoubtedly pseudepigraphical. The general period of the book, as we know from literary style, is somewhere between 200 OCE and 400 OCE, which makes the Abrahamic authorship impossible. And of course, the ideas expressed in the Book are the result of concepts developed in the period just prior to the date suggested by the literary style.
It is thought by some that Rabbi Akiba ben Yosef, a great spiritual genius who also helped lead the Bar Kohkba revolt against the Emperor Hadrian, was the author of the Book. But even his life, which ended about 125 OCE in such tragic and monsterous punishment (it is said the Romans scraped off his skin and burned him alive)¹ is a bit early. A lost treatise on the Hebrew alphabet is traditionally attributed to Rabbi Akiba, but whether the two works are one and the same has by no means been decided. It is certainly possible that the learned martyr was the author of the Book Of Formation, but the matter has yet to be convincingly demonstrated.
The early history of the book, like the date and author, is lost in the shadows of the Dark Ages. The main reason for questioning the Akiba authorship is that the first possible mention of the Book, by no means definite, is in 850 OCE, by Saint Agobard,² and this of course is several centuries too late for Akiba. And, in fact, the Book does not even find mention for another two hundred years, around 1135 OCE, when the distinguished Jewish poet Jehudah ha-Levi, in his famous Al-Kuzari, relied heavily upon the Book in order to prove to the King of the Kuzaries that the ancient Jews (Ha-Levi accepted the Abrahamic authorship of the Book) were adept in "science". Unfortunately, however, this date is much too late, seeing that the doctrinal content of the Book of Formation reflects both the details of Platonic cosmology and the tenor of the Gnosticism of the first centuries of the Christian Era.