Social networks have long been a focus of sociological research. Diverse empirical analyses have contributed to the establishment of network analysis as a solid research program. Only in recent years have networks increasingly become a topic of sociological theory formation and, with the talk of the "network society," also a component of contemporary diagnostics. This introductory volume provides insight into the research and analysis of networks in various application areas. The introduction to key concepts of sociological network analysis is complemented by a discussion of current approaches to a theory of social networks.