"Karl Sigmund helped conceive the field of evolutionary game theory and has dominated it for over thirty years. With "The Calculus of Selfishness," he has written a highly engaging and captivating book for students and experts who want to learn about one of the most fascinating fields of science. When it comes to Karl Sigmund we are all students. This book is written for you and me."--Martin Nowak, Harvard University "In this outstanding and beautiful book, Karl Sigmund extends the theory of games to understand how variations in real social situations alter social outcomes. With elegance, he clarifies the results from different studies, fully develops the concepts of reputation and trust, and gives the foundations for moving the discipline to the next level."--Steven Frank, University of California, Irvine