This commentary outlines the origins, history, and current status of research related to children's social withdrawal and social isolation. Early research related to children's peer relationships is first explored, followed by a discussion of the relative "neglect" of social withdrawal prior to the 1980s. Increased research attention since that time is briefly reviewed; this latter research has provided a greater understanding of the causes, correlates, and consequences associated with "solitude." In the latter half of this essay, the roles of biological factors and parenting are described. The essay closes with a discussion of future directions, including the exploration of risk and protective factors for socially withdrawn children, as well as the need for more research related to prevention and intervention.