Rowan Jacobsen, winner of the James Beard Award, discovered the best chocolate he had ever eaten – a long-lost strain of wild cacao from the Bolivian rainforest. Here's the story of how he tracked it down, journeying by boat into the heart of Amazonia, enduring monstrous ticks, warlike ants, floods, drug runners, fickle outboards, piranha for breakfast, and a tribal helmsman more interested in beer than commerce.