Book excerpt: Social Exchange in Developing Relationships is a collection of papers that deals with the systematic study of the development of relationships. The papers discuss several theoretical perspectives, such as evolutionary theory, personality theory, cognitive developmental theory, equity theory, role theory, and attribution theory. One paper discusses romantic relationships—the evolution of first acquaintance to close or intimate commitment. Another paper presents the hypothesis that the factors causing a relationship to begin will also probably steer intermediate cognitive processes, eventually influencing the nature of the relationship. Commitment requires specific concepts such as input levels contributed to the relationship, duration of these inputs, and their consistency of occurrence. The equity theory suggests that equity principles determine the selection of one's mate and how they (the partners) will get along in the future. One paper analyzes the dynamic theories of social relationships and the resulting research strategies: that the conceptualization of a parameter of a social relationship can affect the choice of data collection techniques and other matters. Sociologists, psychologists, historians, students, and academicians doing sociological research, can benefit greatly from this collection.