Like the bird whose death signaled dangerous conditions in a mine, the demise of animals that once flourished should give humans pause. How is our fate linked to the earth's creatures, and the cycle of flourishing and extinction? Which are the simple workings of nature's order, and which are omens of ecological disaster? Does human activity accelerate extinction? What really causes it? In an illuminating and elegantly written account of the widespread reduction of the world's wildlife, renowned paleontologist Niles Eldredge poses these questions and examines humankind's role in the larger life cycles of the earth, composing a provocative general theory of extinction.