One of the best books to read about how to grow as a whole being or body, mind, spirit. If you really follow this logic you can enhance your mental capacity and your spiritual aura.   Including the Practices and Exercises of Concentration, both Objective and Subjective, and Active and Passive Mentation, an Elucidation of Maya, Guru Worship, and the Worship of the Terrible, also the Mystery of Will-Force.