The real story of AIDS - how it originated with a virus in a chimpanzee, jumped to one human and infected more than 60 million people - is very different from what most of us think we know. Recent research has revealed dark surprises and yielded a radically new scenario of how AIDS began and spread. Excerpted and adapted from Spillover, with a new introduction by the author, Quammen's hair-raising investigation tracks the virus from chimp population s in the jungles off the southeastern Cameroon to laboratories across the globe, as he unravels the mysteries of when, where and how such a consequential 'spillover' can happen. An audacious search for answers amid more than a century of data, The Chimp and the River tells the haunting tale of one of the most devastating pandemics of our time.