Free Ebooks on Meditation and Spirituality?

Fellow yogis,

Who can supply sources for ebooks, ideally free, on spiritual subjects such as meditation, yoga, scriptures, and other aspects of spirituality? In other words, Yoga Vidya!

Three sources stand out from my experience:

• 1. I suppose most readers of the Yoga Vidya site will be familiar with the Divine Life Society's site and their list of free ebooks by Swamis Sivananda, Chidananda, Krishnananda and more. Quite a resource.
• 2. Quite an outstanding resource for students of meditation and the Theravada Buddhist and Thai Forest traditions is Access to Insight. This is a mine of knowledge waiting to be explored.
• 3. The Atma Jyoti website has quite a library of ebooks on meditation and other aspects of spiritual life. A site worth visiting often, as new articles can be found on a regular basis. Also, it is worthwhile subscribing to their blog feed and getting articles on spiritual life emailed you weekly.

I could make more suggestions, but I'll wait to see what others will contribute.