"This work is a record of instruction received during different states of Yoga practice; that sealed book opened by the aspiring student during his development into his own inner states of being." - M (the author). This precious book stands next to Blavatsky's The Secret Doctrine (1888) as one of the most important spiritual books of recent centuries. First published in 1931, at a time when charlatans and fortune-seekers were rapidly expanding their efforts to mislead humanity through mischevious spiritual teachings, this mysterious book by an "anonymous" author opened the doors for sincere seekers to real spirituality. Yet, the author "M" could not state explicitly what was destined to be fully revealed beginning in 1950 by Samael Aun Weor. When illuminated by the light of the ancient Gnostic teachings, the wisdom of this book can truly be understood and valued. Chapters include: Atoms; The Nous Atom; Destructive Atoms; The Astral; Elemental Nature; The Eternal Lover; Nature; Health in Yoga; Advocate and Dweller on the Threshold; Finer Forces; Breathing and Bloodstream; Animal Food; Reincarnation and Karma; Atmospheric Screen and Breathing; Mental Travelling; Masters; Submerged Worlds; The Silver Shield; The Elemental Advocate; Healing; Yoga Techniques; Summary of the Silver Shield; Determinative Energy; An Arcadian Contact; Mantras; Transformation Breathing; Cosmic Rays; Natural Magic; Egypt; Chinese Consciousness; The Element of Fire; The Solar Flame.