Social cohesion is the outcome of the social and physiological processes through which individuals become linked into social systems. These linkages, as they occur in social relationships and are found in small group interactions, are the common focus of this collection of essays. The volume begins with an exploration of social relationships as regulators of physiology and behavior. Other essays investigate issues such as dominance, ideological constraints on evolutionary theory, social cohesion in dyadic groups, social relationships as determinants of emotion and physiology, biosociology and stratification in the works of Emile Durkheim, and the phenomenon of hemispheric lateralization of function in relation to social comparison processes and social roles.