Leakey's personal account of his fossil hunting and landmark discoveries at Lake Turkana, his reassessment of human prehistory based on new evidence and analytic techniques, and his profound pondering of how we became "human" and what being "human" really means. 40 photos.

In Origins Reconsidered, Richard Leakey, one of the most respected and influential scientists of our time, takes us on a brilliant and provocative journey through human history. Beginning with his landmark discoveries at Lake Turkana, and including his fascinating reassessment of how we became "human" - and what, after all, being human really means - Leakey concludes with a glimpse of what our evolutionary future may hold. In 1984, Richard Leakey and his "Hominid Gang" of fossil hunters discovered fragments of a boy's skull that were more than 1. 5 million years old. They soon unearthed virtually the entire skeleton of what was dubbed the "Turkana Boy" and recognized as one of the most significant paleoanthropological discoveries of all time. But while his Turkana Boy caused a sensation in the media and throughout the world of science, Leakey himself was restless. Yes, the existing fossil record of our prehistory was impressive. But there were more elusive matters to consider. For Richard Leakey the most compelling question is no longer "How did we physically evolve?" It is, instead, "How did we become human?" For this world-renowned paleoanthropologist it is a humbling reminder that no matter how complete the skeleton, how perfect the fossil, there is a gap in our knowledge. Our ancestors evolved from two-legged scavengers into creatures that create. They learned to make stone tools, to communicate, to build shelters, and to hunt for food. This realization sparked Leakey to return to his earlier work - especially his 1977 book, Origins - to poke holes in his previous beliefs and to reflect anew on what makes us who we are. As he gently admits, considerations like these are usually left to philosophers, not scientists. But again and again, he is faced with his own guiding principle: "The past is the key to our future. "