Not so much an author as a philosopher but his words on page are always cathartic. I first found out about him through Bill Hicks and the opening of Mudvayne's L.D.50.

McKenna is (was?) a biologist who writes about drugs, correct?

Drugs ain't my scene, but I'm curious as to what McKenna has to say. Any particular titles that you would recommend, Filmore?

He had what he built to be essentially a degree in Shamanism (he died just before the millenium). Right now I'm reading the Archaic Revival but I think if you really want to get into him you should search the web for Tree Of Knowledge. It's fairly easily available for download from a couple websites (only available otherwize on $60 cassette tapes). He had some really cool theories about things like human evolution being spurred from apes via a symbiotic relationship with psilocybin mushrooms. To hear him say it is a lot more impactful than my summaries will ever be. After that, depending on you, you'll either seek out his books or swear it all off as nonsense. He sounds really intelligent though and in the book I'm reading, he explains where Timothy Leary went wrong (which I've always been curious about).