A social network is a social structure made up of a set of social actors (such as individuals or organizations), 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. 

Social networks and the analysis of them is an inherently interdisciplinary academic field which emerged from social psychology, sociology, statistics, and graph theory. Georg Simmel authored early structural theories in sociology emphasizing the dynamics of triads and "web of group affiliations". Jacob Moreno is credited with developing the first sociograms in the 1930s to study interpersonal relationships. These approaches were mathematically formalized in the 1950s and theories and methods of social networks became pervasive in the social and behavioral sciences by the 1980s. Social network analysis is now one of the major paradigms in contemporary sociology, and is also employed in a number of other social and formal sciences. Together with other complex networks, it forms part of the nascent field of network science.
Who created the first sociograms? when? What for? What did Georg Simmel write? Dealing with dynamics of what? What does a social network consist of? What happens between actors? What give a set of methods? Does this analyze just part of the social parts? How much? What do the theories explain? What is one reason to study this? What's another? Do you know of any more? Does studying social networks just include one field? How many did it come from? What are they? How was this formalized in the 50s What field of science is this part of? Is it part of modern sociology?
Jacob Moreno the 1930s to study interpersonal relationships early structural theories in sociology triads a set of social actors (such as individuals or organizations) and sets of dyadic ties social interactions The social network perspective no whole social entities the patterns observed in these structures to identify local and global patterns to locate influential entities to examine network dynamics no Four social psychology, sociology, statistics, and graph theory mathematically network science yes