The Book of Concealed Mystery is a mystical and esoteric text written by S. L. MacGregor Mathers, a prominent occultist and founding member of the Hermetic Order of the Golden Dawn. The book is a translation of a medieval Jewish mystical text called Sefer ha-Razim, which is believed to date back to the 3rd century CE.The Book of Concealed Mystery is divided into two parts. The first part is a series of prayers and invocations that are designed to...