Trust and Reciprocity explores the contributions of behavioral economics, laboratory experiments, and field experiments to our understanding of the economics of trust, trustworthiness, and reciprocal behavior. The monograph begins with a general summary presenting the evolution of trust and reciprocity, departing from pure self-interest in the understanding of homo economicus . Next, an exploration of the games and academic contributions that isolate preferences (including social preferences, altruism, inequality aversion, and guilt aversion) from pledges of trust and from reciprocal behavior provides a foundation for behavior that is often misidentified as trust or conditional upon the actions of another. The monograph concludes with a summary of theory and experiments that have identified trust and reciprocity in economics and human behavior.