Neil Shubin, a leading paleontologist and professor of anatomy who discovered Tiktaalik--the "missing link" that made headlines around the world in April 2006--tells the story of evolution by tracing the organs of the human body back millions of years, long before the first creatures walked the earth. By examining fossils and DNA, Shubin shows us that our hands actually resemble fish fins, our head is organized like that of a long-extinct jawless...