Detention is among the most controversial and complex powers a state can exercise over an individual, raising the fundamental question: how can a liberal state justify restricting the liberty of certain individuals for the security of others, while still upholding the dignity of those whose freedom is curtailed?Punishment, Penalty, and Incapacitation seeks to answer that question by distinguishing four types of justification for targeted restrictions of liberty: deserved punishment, forfeiture of rights, enforceable duties to self-restrict, and lack of accountability. This book maintains that targeted restrictions of liberty must appeal to one of the four justifications listed above, and that each type of justification imposes characteristic limits on the way restrictions can operate. Drawing on a wide range of legal and political sources, this book offers a foundational inquiry into the theory of detention and other targeted limits on liberty, and develops a rigorous model for their justification in liberal democratic states.