How do the hard facts of political responsibility shape and constrain the demands of ethical life? That question lies at the heart of the problem of ‘dirty hands’ in public life. Those who exercise political power often feel they must act in ways that would otherwise be considered immoral: indeed, paradoxically, they sometimes feel that it would be immoral of them not to perform or condone such acts as killing or lying. John Parrish offers a wide-ranging account of how this important philosophical problem emerged and developed, tracing it – and its proposed solutions – from ancient Greece through the Enlightenment. His central argument is that many of our most familiar concepts and institutions – from Augustine’s interiorised ethics, to Hobbes’s sovereign state, to Adam Smith’s ‘invisible hand’, understanding of the modern commercial economy – were designed partly as responses to the ethical problem of dirty hands in public life.