Social scientists have been slow to appreciate the great diversity among the poor. Until quite recently, researchers have devoted more attention to examining patterns of persistent poverty than to understanding how individuals and families maneuver their way out of economic disadvantage (for exceptions, see Clark, 1983; Kellam, Ensminger, & Turner, 1977; Williams Kornblum, 1985). Evidence about mobility patterns among the poor provides a perfect analogy to the half-empty/half-full glass. Of individuals who begin life in poverty, at least as many manage to improve their circumstances as remain persistently impoverished (Duncan, Hill, & Hoffman, 1988). Yet relatively little is known about how and why some of the disadvantaged eventually escape while others remain entrapped in poverty. As researchers from different disciplines have begun to tackle this problem, they have, not surprisingly, each featured explanations congenial to their distinctive ways of looking at the world. Economists stress the importance of financial and human capital, highlighting how individuals invest time and money to improve their long-term position in the labor force (Palmer, Smeeding, & Torrey, 1988). Psychologists point out the importance of individual traits such as competence and self-efficacy, both of which are linked to upward mobility (Bandura, 1989; Garmezy, 1985; Rutter & Madge, 1976; Werner & Smith, 1982). Sociologists, for their part, underscore the importance of institutional resources and social networks in the communities where poor people reside (Granovetter, 1973; Wellman 8t Wortley, 1990). Of course, in reality these different sorts of mechanisms often operate in tandem. Perhaps the most interesting question, then, is how these various sources of differentiation among the poor are packaged together. Answering the question of how id why certain types of individuals locate and use resources that are often in short supply within their local environments to improve their own prospects, or the long-term prospects of their children, involves integrating the different disciplinary perspectives. This article draws on data from a longitudinal study of teenage mothers and their children to investigate sources of differentiation on several indicators of young adult success. In particular, we explore the role of social capital, a concept developed by Coleman (1988) that to some extent bridges the disciplinary gaps described above. Our goal is to determine whether successful outcomes among our sample of disadvantaged youth are related to measures of both family-based and community-based social capital. SOCIAL CAPITAL AND YOUTH DEVELOPMENT The process of investment in the economic, psychological, and social resources believed to be associated with upward mobility begins early in life and typically takes place within the family. Parents, in addition to utilizing their financial resources, cultivate and promote individual competencies in their children; with varying degrees of effectiveness, these same parents seek opportunities in the environment and attempt to shelter their children from dangers. Thus, the family represents a point of common interest to social scientists seeking to understand why and how certain children are able to escape the powerful disadvantage of growing up poor. Coleman (1988) employed the term social capital to designate the complex and variegated social mechanisms that parents garner to advance their children's chances of success. Coleman's description of social capital is quite broad and overlaps with some of the specific theoretical constructs and processes identified by developmental psychologists attempting to explain the successful adaptation of children at risk of long-term disadvantage (see, e.g., Garmezy & Rutter, 1983). Coleman's ideas also echo the approach to studying development formulated by Bronfenbrenner and his students (e.g., Bronfenbrenner, 1979; Garbarino, 1992; Steinberg, Dornbusch, & Brown, 1992). …