Richard D. Alexander is an accomplished entomologist who turned his attention to solving some of the most perplexing problems associated with the evolution of human social systems. Using impeccable Darwinian logic and elaborating, extending and adding to the classic theoretical contributions of pioneers of behavioral and evolutionary ecology like George Williams, William Hamilton and Robert Trivers, Alexander developed the most detailed and comprehensive vision of human social evolution of his era. His ideas and hypotheses have inspired countless biologists, anthropologists, psychologists and other social scientists to explore the evolution of human social behavior in ever greater detail, and many of his seminal ideas have stood the test of time and come to be pillars of our understanding of human social evolution. This volume presents classic papers or chapters by Dr. Alexander, each focused on an important theme from his work. Introductions by Dr. Alexander’s former students and colleagues highlight the importance of his work to the field, describe more recent work on the topic, and discuss current issues of contention and interest.