I'd recommend Henry Miller's Tropic of Capricorn, in the interest of 'mystical'. He was not on LSD as far as I'm aware, and everything he wrote was long before any of that really got started but the flavor of his writing as well as the deep, ruminative exposition and captioning of his own human experience was reminiscent to me of many philosophical writers and later fiction likely influenced by his work. His words themselves are psychedelic, and I don't think any other book has so far made me laugh so hard I couldn't see the page. This man was an angel.
Also, Blood Meridian ('or the Evening Redness in the West'
![Pleased](/forum/images/emoticons/happy.png)
by Cormac McCarthy. It is a fiction, and again not much 60's and 70's pop culture influence so far as I can tell, but highly entertaining and even spiritual though it was not intended to be. He is prose from top to bottom, and all fire. There is an endless wealth of passages from this book alone that I would spam without hesitation any forum's quotes section with pleasure. He also wrote No Country for Old Men, which is another great one but not as relevant here.
I would also stand behind Euphor's suggestion, 'The Yaqui Way' had a very powerful message were it a faithful account, pure fantasy or what. There is one particularly hilarious peyote trip report in there I remember that I felt also demonstrated the good nature of the company he kept in that time frame, also.
And of course, an obligatory,
Fear and Loathing in Las Vegas.