Raziel is an angel, or Ophanim who is the "Keeper of Secrets" and the "Angel of Mysteries". He is also addressed as the Secrets of God. The book he carries, known as the Book of Raziel, along with teachings that were attributed to this figure is said to contain all secret knowledge, and is considered to be a book of magic. He stands close by God's throne, and therefore hears and writes down everything that is said and discussed.
It is even believed that he purportedly gave the book to Adam and Eve after they ate from the forbidden Tree of Knowledge of Good and Evil (for which resulted in their expulsion from the Garden of Eden) so the two could find their way back "home" and better understand their God.
Raziel's fellow angels were deeply disturbed by this, and thus stole the book from Adam and threw it into the ocean. God Himself decided not to punish Raziel, but instead retrieved the book by means of the angel Raphael and returned it to Adam and Eve. This legend is said to be similar to the story of Prometheus from Greek mythology after he introduced fire to mankind.