Debates about social capital usually focus on its presumed positive consequences. Although this expectation has been corroborated empirically, in many instances some less benign consequences of social capital have also been uncovered. Several explanations for the emergence and consequences of these "dark sides" of social capital are briefly presented here and, subsequently, put to empirical testing. The contributors to this issue of American Behavioral Scientist have a common understanding of these dark sides of social capital. Conceptualizing them as negative consequences or outcomes, the authors use various research strategies to scrutinize the nature of the effects of social capital in various situations. In each analysis, however, particular focus is placed on the importance of the contextual setting. Special attention is paid to the degree of democratization, the postcommunist legacy, different welfare state regimes, the saliency of political cleavages, and types and interconnectedness of voluntary associations. The findings suggest that the specific consequences of social capital largely depend on political and social conditions.