Earth has experienced five major mass extinction events over the last half-billion years, each fundamentally altering the course of life on our planet. Today, scientists warn that we are currently in the midst of a sixth, human-driven extinction, as rapid climate change, habitat destruction, and pollution threaten the survival of countless species. By examining the fossil record, researchers can better understand the catastrophic forces that have shaped our world and the precarious future that lies ahead for all living things.