This book is a book written by Edward O. Wilson, a biologist and environmental advocate. The book discusses the threat of mass extinction, known as the Sixth Extinction, taking place at humanity’s own hands. Wilson proposes an achievable plan to save our imperiled biosphere: devote half the surface of the Earth to nature. The book argues that the situation facing us is too large to be solved piecemeal and proposes a solution commensurate with the magnitude of the problem: dedicate fully half the surface of the Earth to nature.