4.5 stars. I love the Author's hypothesis and his final thoughts tying drug use and religion/spirituality together from the earliest antiquity to today. Although I appreciated his attempt to write the story as a journey or adventure uncovering as he goes, I did have a hard time following all the names and places at times, and felt he reiterated himself quite a bit. But hey, it's non fiction, you gotta give it a break, right?