Spiritual development and psychological evolution take many forms. Regardie happened to be one of the most interesting purveyors of magick in the tradition of Crowley and even further back, the original mystics and occult greats.
What is fascinating to me is that despite Regardie's well-known ego clashes with Crowley, the original theories are expounded upon in a similar tradition to that of Jung carrying Freud's theories forward. Regardie took the intellectual baton from Crowley and ran with it in a particularly enriched, highly articulate way. Lots of good stuff here.
A must for anybody serious. In this age of Hollywood spurred interest in mysticism, it is easy to be misled by trendy authors with overblown egos. Keeping mental and emotional equilibrium is vital to spiritual growth and development of abilities. Most of the people who post on this subject matter would benefit greatly by this book.