read this Cleansing the Doors of Perception by Huston Smith Phd

Smith, widely regarded as the most eloquent and accessible contemporary authority on the history of religions. A leading figure in the comparative philosophy of religion, he has taught at Washington University, MIT, and Syracuse University and author of The World's Religions: Our Great Wisdom Traditions, a standard introduction to its eponymous subject since its first publication in 1958.

http://www.amazon.com/exec/obidos/t...f=sr_1_8/104-6308244-5514351?v=glance&s=books

also read this article

Do Drugs Have Religious Import? by Smith

http://www.druglibrary.org/schaffer/lsd/hsmith.htm