Can we rely on the altruism of professionals or the public service ethos to deliver good quality health and education services? And how should patients, parents, and pupils behave - as grateful recipients or active consumers? This book provides new answers to these questions - a milestone in the analysis and development of public policy, from one of the leading thinkers in the field. It provides a new perspective on policy design, emphasising the importance of analysing the motivation of professionals and others who work within the public sector, and both their and public service beneficiaries' capacity for agency or independent action. It argues that the conventional assumption that public sector professionals are public-spirited altruists or 'knights' is misplaced; but so is the alternative that they are all, in David Hume's terminology, 'knaves' or self-interested egoists. We also must not assume that individual citizens are passive recipients of public services (pawns); but nor can they be untrammelled sovereigns with unrestricted choices over services and resources (queens). Instead, policies must be designed so as to give the proper balance of motivation and agency.