This study is the first large-scale comparison of policy and divergence in the UK since devolution. It identifies the different combinations of market, profession, management and civil society that England, Northern Ireland, Scotland, and Wales chose in their efforts to provide health services to all. It explains why these four health systems, despite facing similar pressures and opportunities, have developed dramatically different health policy trajectories. Based on extensive original research in the UK, Canada and Spain, it argues that we should expect substantial divergence in policies and social citizenship in the UK as its autonomous political systems try to solve the unpredictable and difficult puzzles of health policy-making. This book's combination of a focus on the policies and politics of all parts of the UK, nuanced analysis of the politics of medicine and political institutions, and comparative analysis of devolution make it an important contribution to debates about health policy, devolution, and the comparative politics of the welfare state.