The path to mystical attainment or enlightenment was initially developed by Crowley largely based on the meditation/mystical techniques found in Buddhism and also the Tree of Life, especially as it was examined by Eliphas Levi in the 19th century and later by various members in the occult society, the Golden Dawn. In 1904, Crowley claimed to have transcribed, via "direct-voice transmission" from a "praeternatural intelligence" named Aiwass, The Book of the Law, which he eventually called the central sacred text of Thelema, heralding a new Aeon for mankind.
Between 1907 and 1911, Crowley wrote a series of other small texts which he considered to be "inspired" in that they were written through him rather than by him, which were afterwards collected together and termed the Holy Books. The final text added to the list was The Vision and the Voice, a vivid account of Crowley's astral travels through the thirty Enochian Aethyrs. These texts formed the final mystical backbone of Crowley's system.
Free eBooks (Can Be Downloaded):
Arthur Edward Waite - The Hermetic MuseumFrederick Hadland Davis - The Persian Mystics Jami
Roman Tertius Sibellius - De Vermis Mysteriis
Reynold Nicholson - The Mystics Of Islam