Inter-organizational networks have proliferated in health systems, as has network research, but coherent explanations relating the varieties of health network to their respective structures, activities and outcomes remain lacking. Focusing on their core productive processes and their governance structures, this chapter contrasts care networks with program networks. It compares these concepts with findings from some primary research on NHS health networks during 2005–10, and notes some implications for network theory and research. NHS networks’ dense, flat structures reflect these networks’ dual function as both care and as program networks. These findings are relevant to the “integrated care” networks developing in many health systems. The development of these networks appears, partly, to be a workaround for the obstacles that market and quasi-market health systems place in the way of coordinating complex care across multiple separate providers.