Barry Wellman is an American-Canadian sociologist and is the co-director of the Toronto-based international NetLab Network. His areas of research are community sociology, the Internet, human-computer interaction and social structure, as manifested in social networks in communities and organizations. His overarching interest is in the paradigm shift from group-centered relations to networked individualism. He has written or co-authored more than 300 articles, chapters, reports and books. Wellman was a professor at the Department of Sociology, University of Toronto for 46 years, from 1967 to 2013, including a five-year stint as S.D. Clark Professor.

A social network is a social structure made up of a set of social actors, sets of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures. The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and examine network dynamics.