More than three hundred million years ago - a relatively recent date in the two billion years since life first appeared - vertebrate animals first ventured onto land. This usefully illustrated book describes how some finned vertebrates acquired limbs, giving rise to more than 25,000 extant tetrapod species. Michel Laurin uses paleontological, geological, physiological, and comparative anatomical data to describe this monumental event. He summarizes key concepts of modern paleontological research, including biological nomenclature, paleontological and molecular dating, and the methods used to infer phylogeny and character evolution. Along with a discussion of the evolutionary pressures that may have led vertebrates onto dry land, the book also shows how extant vertebrates yield clues about the conquest of land and how scientists uncover evolutionary history.