It is the ultimate mystery: where do we come from? In 1994, a team led by fossil-hunting legend Tim White uncovered a set of ancient bones in Ethiopia's Afar region. Radiometric dating of nearby rocks indicated the resulting skeleton, classified as Ardipithecus ramidus-nicknamed "Ardi"-was an astounding 4.4 million years old, more than a million years older than the world-famous "Lucy." The team spent the next 15 years studying the bones in strict secrecy, all while continuing to rack up landmark fossil discoveries in the field and becoming increasingly ensnared in bitter disputes with scientific peers and Ethiopian bureaucrats. When finally revealed to the public, Ardi stunned scientists around the world and challenged a half-century of orthodoxy about human evolution-how we started walking upright, how we evolved our nimble hands, and, most significantly, whether we were descended from an ancestor that resembled today's chimpanzee. But the discovery of Ardi wasn't just a leap forward in understanding the roots of humanity--it was an attack on scientific convention and the leading authorities of human origins, triggering an epic feud about the oldest family skeleton.