Discretion is a pervasive phenomenon in legal systems. It is of concern to lawyers because it can be a force for justice or injustice: at once a means of advancing the broad purposes of law and of subventing them. For social scientists the discretion exercised by legal actors is an important form of decision-making behaviour, in which legal rules are merely one force in a field of pressures and constraints that push towards certain courses of action or inaction. This book presents a variety of analyses of legal discretion by lawyers and social scientists (drawn from both sides of the Atlantic), who have made discretion and its uses a central part of their scholarly concerns.