by Aldous Huxley
This is a well-known treatise on altered perceptions and is loosely categorized as Philosophy.
The Doors of Perception is largely about the author's experience of mescaline and the altered mental perceptions of the world he experienced under the influence of the drug. I have to admit that I was a little disappointed with the limited viewpoint as this could have been much more interesting with input by other people, especially native American people who have traditionally used Peyote for spiritual questing in their rituals.
The sequel, Heaven and Hell, goes more into the philosophical musings that I was interested to find. In this follow-up, Huxley discusses correlations between hallucinogenic drug experience, especially the heightened sense of color, and religious experience as well as the natural attraction our species has to gemstones and flowers with bright colors.
It made for dry reading, yet had some interesting points. The rock band, The Doors, named themselves for this book so curiosity made me want to read it. I wouldn't recommend it for deep Philosophy, but it was interesting in parts and blissfully short. Reading a few pages at a time worked for me to keep from letting the boredom mask the worthwhile insights.