The composition of associations, including social movements, and their impact on the political system is well known (see Kellerhals 1974 and 1989; Giugni 1995), but the nature of a connection between the participation of individuals in voluntary associations and their participation in politics is still open to question. The most common hypothesis, as van Deth reminds us in the first chapter of this book, is one of social or associative participation serving a socializing and integrating function which tends to strengthen political participation, along the lines of Putnam’s social capital model (Putnam 1995).1 The difficulty in any such analysis, however, is the absence of a single concept ‘participation’. Thus, the approach to associative participation may encompass the work of groups conducting local campaigns and groups essentially for leisure purposes, as well as degrees of participation ranging from those requiring only financial contributions to those requiring a greater personal involvement (see Maloney and Jordan, this volume). Similarly, there are numerous definitions of political participation (Memmi 1985:311): most work on the basis of voluntary acting and an active individual reflecting either conventional forms of participation or those regarded as alternatives. We shall seek to highlight these various concepts of participation during the course of our analysis, and in particular pay attention to the distinction between conventional political participation and participation in social movements.