Social networks dominate modern life. Social networks have always existed and have been around in nonelectronic forms throughout the entirety of our species' history. It is only recently that the Internet has provided a venue for their electronic explosion. From a nonexistent phenomenon to an incessantly repeated buzzword that permeates the media and is the topic of a major Hollywood film, electronic social networks experience such success because human social behavior has been naturally selected to interface in such a way. Genes and culture relentlessly encourage sociality, and network structure is the grand output of countless interactions in which we engage, from winks to weddings. With the advent of technology that promotes these connections, our innate propensity to connect at a large scale is changing the way we live. From mundane communication to meeting the love of one's life to inciting political revolutions, network ties are the conduits by which information and resources are spread. Understanding the patterns and more importantly the “whys” of human connectedness can greatly impact quality of life for the better. The present article reviews the extant literature of social networks and social network analysis proper, the evolutionary foundation of social networks, the proposed psychological antecedents of network composition, the transition from traditional to online networks and how the two modes differ, the impact of social networks on popular culture, and the future of social networks.