Coevolution - reciprocal evolutionary change in interacting species driven by natural selection - is one of the most important ecological and genetic processes organizing the earth’s biodiversity: most plants and animals require coevolved interactions with other species to survive and reproduce. The Geographic Mosaic of Coevolution analyzes how the biology of species provides the raw material for long-term coevolution, evaluates how local coadaptation forms the basic module of coevolutionary change, and explores how the coevolutionary process reshapes locally coevolving interactions across the earth’s constantly changing landscapes. Picking up where his influential The Coevolutionary Process left off, John N. Thompson synthesizes the state of a rapidly developing science that integrates approaches from evolutionary ecology, population genetics, phylogeography, systematics, evolutionary biochemistry and physiology, and molecular biology. Using models, data, and hypotheses to develop a complete conceptual framework, Thompson also draws on examples from a wide range of taxa and environments, illustrating the expanding breadth and depth of research in coevolutionary biology.