Ideals are important in social reality, but they have been neglected in theories of law, politics, and morality. This book has the role of ideals as its central theme. More specifically, it argues that ideals are necessary to understand pluralism, that they are key elements in controversy and debate, and that they enable development. It combines theoretical analysis of the concept of ideals with discussion of concrete debates and cases, including philosophical debates about politics and equality, sociological studies of the diverse interpretations of the rule of law, and accounts of the development of environmental law and privacy law. Thus, the functioning of ideals is critically examined, showing the merits and limitations of an ideal-oriented approach.