The Tree of Life - Israel Regardie
This book is one of the few definitive established guides to the kabbalah of the Western Mystery Tradition. Israel Regardie sets out the principles concinsely and clearly. Kabbalah such as the Tree of Life, the Sephiroth, magical correspondences and weapons of the art, and much more. He discusses the training of the magical will, yoga, pranayama, mantras and the use of barbarous names of evocation; the use of god-forms and the importance of the Holy Guardian Angel. He also includes examples of ritual magic operations and discusses thorny issues such as the relationship between magic and Spiritualism. The author draws upon his experience in the Order of the Golden Dawn and his time studying under Aleister Crowley, and the resulting work, though not long, is masterful.