Robert H. MacArthur and Edward O. Wilson’s The Theory of Island Biogeography, first published by Princeton in 1967, is one of the most influential books on ecology and evolution to appear in the past half century. By developing a general mathematical theory to explain a crucial ecological problem — the regulation of species diversity in island populations — the book transformed the science of biogeography and ecology as a whole. In The Theory of Island Biogeography Revisited, some of today’s most prominent biologists assess the continuing impact of MacArthur and Wilson’s book four decades after its publication. Following an opening chapter in which Wilson reflects on island biogeography in the 1960s, fifteen chapters evaluate and demonstrate how the field has extended and confirmed — as well as challenged and modified — MacArthur and Wilson’s original ideas. Providing a broad picture of the fundamental ways in which the science of island biogeography has been shaped by MacArthur and Wilson’s landmark work, The Theory of Island Biogeography Revisited also points the way toward exciting future research.