The Evolution of Cooperation is a 1984 book by political scientist Robert Axelrod that expanded a highly influential paper of the same name, and popularized the study upon which the original paper had been based. Since 2006, reprints of the book have included a foreword by Richard Dawkins and been marketed as a revised edition. "The Evolution of Cooperation" is a 1981 paper by Axelrod and evolutionary biologist W. D. Hamilton in the scientific literature, which became the most cited publication in the field of political science.