The policy network tradition evolved partly out of the debate between corporatism and pluralism. In particular, the inability of both to account for variation between policy sectors proved an important starting point for, and focus of, network analysis. This chapter reviews four different network approaches in the light of the emphasis each of them puts on structure and agency respectively in explaining policy outcomes. It explores whether one should perceive a policy network as a metaphor for a pattern of interaction or give it explanatory force by emphasising that the network structure is an important determinant of policy outcomes. Jordan, Richardson and their associates view the drive towards fragmentation and specialisation as part of the logic of the modern policy process which implies that real policy making takes place in sub-sectoral policy communities. The chapter concludes that the policy network structure itself is an important variable influencing policy outcomes.