When Donald Johanson found a partial skeleton, approximately 3.5 million years old, in the remote Afar region of Ethiopia in November 0f 1974, he knew he had stumbled onto something unique. Bursting with all the suspense and intrigue of a fast-paced adventure novel, and filled with lively, up-to-the-minute scientific detail and marvelous illustrations in color and black-and-white, this major n…