Over billions of years, ancient fish evolved to walk on land, reptiles transformed into birds that fly, and apelike primates evolved into humans that talk and write. For more than a century, paleontologists have traveled the globe to find fossils that show how such changes have happened. As Neil Shubin recounts here, we have now arrived at a remarkable moment—new DNA technology has given us the tools to answer some of the basic questions of our existence, including: Is our presence on Earth the product of mere chance?