From antiquity until the advent of Christianity, the tradition remains alive that every person comes into life accompanied by a luminous entity that protects and guides them in their daily life. But what is this entity? A consolation for appeasing our fears? A divine messenger or an unconscious aspect of our true Self? The book of Abramelin, written in 15th-century Germany, remains to this day the most discussed work among Western occult literature, as it is entirely dedicated to the method for the knowledge and communication with the Holy Guardian Angel. This volume presents for the first time in Greek the entirety of the book as it was translated in 1889 by MacGregor Mathers of the Hermetic Order of the Golden Dawn, while also conducting a comparative analysis with an older German manuscript. The Grimoire, along with all the Magical Squares, is accompanied by an introduction by psychologist & author George Ioannidis on the history of the book, its origins in medieval angelic magic, as well as the roots of Abramelin's broader worldview in the Neoplatonic teachings of Theurgy.