Political-science research on social capital has burgeoned in the past few years.I must thank Shayla C. Nunnally, doctoral student in political science at Duke University, for introducing me to much of the social-capital literature in political science through the chapters of her dissertation. Robert Putnam says that the concept has been invented at least six times during the twentieth century, and its definition has been reconceived. Much current research uses Putnam's definition of social capital—“features of social organizations, such as trust, norms, and networks, that can improve the efficiency of society by facilitating coordinated actions.”Putnam 2000, 19; Putnam 1993, 167. Yet political science does not have a corner on the market of research when it comes to studying the concept. Research on social capital has been done—and is being done— in economics, geography, history, demography, sociology, African studies, African American studies, Asian studies, education, ecology, and psychology.A quick search of JSTOR and PsychInfo on the concept— restricted to each discipline's journals—reveals the wealth of research on social capital in articles published since the early 1900s. The earliest appearance of a reference to the concept in a political science journal that I was able to identify was in a 1905 article in Political Science Quarterly, “The Field of Economic Dynamics” by John Bates Clark. Clark's definition of social capital, however, was within the context of labor and the accumulation of capital. In some instances, these disciplines have used the same definition for the term as political science has; in others, that has not been the case. Despite differences in definition, how might other disciplines' research inform our assessment of the effects of social capital? Conversely, what might political science offer to other disciplines to inform their analyses?