Idries Shah 
Way of the Sufi 

The Way of the Sufi presents an unparalleled cross-section of material from Sufi schools, teachings and classical writings, as a basic course of Sufi study. The author begins with the outward aspects of the teaching most likely to puzzle the student coming fresh to the subject. He considers various attitudes to Sufi ideas, and evidence of their absorption into medieval Christianity, Hinduism, Jewish mysticism and modern philosophical teachings. The greater part of the book illuminates aspects of Sufi activity and practice relevant to the contemporary world.