This paper describes central topics in our research program on social preferences. The discussion covers experimental designs that discriminate among alternative components of preferences such as unconditional altruism, positive reciprocity, trust (in positive reciprocity), negative reciprocity, and fear (of negative reciprocity). The paper describes experimental data on effects of social distance and decision context on reciprocal behavior and male vs. female and group vs. individual differences in reciprocity. The exposition includes experimental designs that provide direct tests of alternative models of social preferences and summarizes implications of data for the models. The discussion reviews models of other-regarding preferences that are and are not conditional on others’ revealed intentions and the implications of data for these models.