
The world's most renowned authorities on the botany and chemistry of hallucinogens have produced an exhaustive study of psychoactive flora. The properties of the plants and the use made of them by man are examined and detailed by botanist Richard Evans Schultes and chemist Albert Hofmann. Their text is accompanied by many illustrations, over a hundred of which are in color.
Plants of the Gods: Their Sacred, Healing, and Hallucinogenic Powers by Richard Evans Schultes (Author), Albert Hofmann (Author), Christian Rätsch (Author)
The Psychedelics Experience by Peter Stafford
Pikhal by Alexander Shulgin
Acid Dreams by Lee and Shlain
The Illuminatus Trilogy by Shea and Wilson
Plants of the Gods by Richard Evans Schultes
The Archaic Revival by Terrence McKenna
The Psychedelic Explorer's Guide by James Fadiman
That should get you started. Good luck, and have a safe trip.