Reddit reviews The Secret Doctrine: The Classic Work, Abridged and Annotated

I'm not sure about essential to every occult library (and I realize some of these aren't necessarily considered primarily 'occult' texts), but here are a few I've found useful:

• The Golden Dawn - Israel Regardie
  
• Morals and Dogma - Alfred Pike
  
• Modern Magick - Donald Michael Kraig
  
• The Secret Teachings of All Ages - Manly P. Hall
  
• Initiation into Hermetics - Franz Bardon
  
• Sefer Yetzirah - Aryeh Kaplan
  
• The Secret Doctrine - Madame Blavatsky
  
• Liber Null & Psychonaut - Peter J. Carroll
  
• The Book of Thoth - Aleister Crowley
  
• Undoing Yourself with Energized Meditation and Other Devices - Christopher S. Hyatt
  
• Prometheus Rising - Robert Anton Wilson
  
• Enochian Vision Magick - Lon Milo DuQuette
  
• The Chicken Qabalah - Lon Milo DuQuette
  
• Brain Magick - Philip Farber
  
• Info-Psychology - Timothy Leary
  
• Beelzebub's Tales to his Grandson - George Gurdjieff
  
• Initiation, Human and Solar - Alice Bailey
  
• The Red Book - Carl Jung
  
• Principia Discordia - Malaclypse the Younger

The Sepher Yetzirah

Agrippa's Three Books on Occult Philosophy

The Pistis Sophia

The Secret Doctrine

The Book of the Law

The Book of Abramelin

• http://www.amazon.com/The-Middle-Length-Discourses-Buddha/dp/086171072X
  
  
• http://www.amazon.com/Tao-Te-Ching-Laozi/dp/0060812451
  
  
  
  And if you want to more obscure but real religions:
  
  
• http://www.amazon.com/All-One-Wicca-Kaatryn-Macmorgan-Douglas/dp/0615150942
  
  
• http://www.amazon.com/The-Secret-Doctrine-H-P-Blavatsky/dp/158542708X
  
  
• http://www.amazon.com/Book-Law-Illustrated-Aleister-Crowley-ebook/dp/B00I45A54Y
  
  
• http://www.amazon.com/Dianetics-Modern-Science-Mental-English/dp/140314446X
  
  
• http://www.amazon.com/Satanic-Bible-Anton-Szandor-Lavey
  
  
  And if you want to be very snarky:
  
  
• http://www.amazon.com/Principia-Discordia-Malaclypse-Younger/dp/1559500409
  
  
• http://www.amazon.com/The-Gospel-Flying-Spaghetti-Monster/dp/0812976568