Amazon – The Serpent & the Rainbow – A really pacey read that keeps the pages turning. Fascinating and well written, this book focuses on the story rather than the cold hard facts, but that’s not to say its not useful. Probably your best starting point.
Amazon – Passage of Darkness – Same author, but a more academic approach to the facts of the case and more detailed concerning the analysis of the ‘poisons’ obtained by Wade Davis. If you go for “The serpent and the Rainbow” and enjoy it, this is the natural next step.