Emphasising the critical importance of policy research and theorising for health care, the Research Handbook argues that analysts of health care policy need to draw on conceptual models of the policy process, in particular the 'stages model' and the '3 Is' model of ideas, interests, and institutions. It considers how these models could be applied using specific cases of countries and regions across the globe, bridging the divide between the existing literature on health systems in the global North and global South.