Nonfiction:
I finished Hippie by Barry Miles a few weeks ago.. It's just a narrative of stories, history, quotations, as well as hundreds of photos highlighting 1965-1971. It's super interesting and I love all the pictures..
Nonfiction-ish:
I enjoy Carlos Castaneda's books: The Teachings of Don Juan: A Yaqui Way of Knowledge -and- A Separate Reality. These are supposed to be non-fiction, but this has been a topic of debate since they were published. Lots of descriptions of peyote, mushrooms, etc., and very entertaining!