Three perspectives on the efficacy of social capital have been explored in the public health literature. A "social support" perspective argues that informal networks are central to objective and subjective welfare; an "inequality" thesis posits that widening economic disparities have eroded citizens' sense of social justice and inclusion, which in turn has led to heightened anxiety and compromised rising life expectancies; a "political economy" approach sees the primary determinant of poor health outcomes as the socially and politically mediated exclusion from material resources. A more comprehensive but grounded theory of social capital is presented that develops a distinction between bonding, bridging, and linking social capital. It is argued that this framework helps to reconcile these three perspectives, incorporating a broader reading of history, politics, and the empirical evidence regarding the mechanisms connecting types of network structure and state-society relations to public health outcomes.