[Excerpt] The causes and consequences of the decline of the American labor movement over recent decades have been examined in countless books and articles. Scholars and commentators, however, have virtually ignored one critical dimension. In this chapter, we focus on the social capital implications of the relative decline of the labor movement. There are several definitions of the term social capital. For our purposes, a relevant definition has been provided by the World Bank: 'Social capital refers to the institutions, relationships, and norms that shape the quality and quantity of a society's social interactions... Social capital is not just the sum of the institutions which underpin a society - it is the glue that holds them together.' The concept of social capital can be traced to the early part of the twentieth century and was implicitly used by philosophers as early as the eighteenth century. But recent research on social capital has been triggered largely by the work of Robert Putnam, especially his seminal books, Making Democracy Work (Putnam, 1993) and Bowling Alone (Putnam, 2000; Coleman, 1990; Adler and Kwon, 2002; Portes, 1998).