First published in 1972 and now available for the first time in paperback, this book is the summation of the life work of one of the most influential scientists of our time. Of permanent interest in the history and philosophy of science, it is also frequently cited in the current ecological literature and is still up-to-date in many categories. "The theme running through this book," MacArthur wrote, "is that the structure of the environment, the morphology of the species, the economics of species behavior, and the dynamics of population changes are the four essential ingredients of all interesting biogeographic patterns." Written in his beautifully lucid style, this work will continue to be read by anyone concerned with biological ideas.