Annie Besant 
Esoteric Christianity [PDF ebook] 
Or the Lesser Mysteries

Religious historian Annie Besant offers a new take on standard Christian doctrine and practice in Esoteric Christianity. Building on the precept that Christianity is actually a mystery religion (i.e., one that relies on the inner knowledge or Gnosis of a spiritual teacher or mystic), this book explores some of the connections between Christianity and practices such as alchemy, astrology, and ritual magic, and discusses the implications of these points of correspondence.