Book excerpt: Toleration plays a key role in liberal thought. This book explores our current understanding of toleration in liberal theory and practice. Toleration has traditionally been characterized as the willingness to put up with others or their actions or practices despite the fact that one considers them as objectionable. Toleration has thus been regarded as one of the core aspects of liberalism: as an indispensable democratic virtue and as a constitutive part of liberal political practice. In modern liberal societies, where deep disagreements about social values and ways of life are widespread, toleration still seems to be of crucial importance. However, contemporary debates on toleration cover an immense variety of theoretical and political issues ranging from controversies over its exact understanding and conceptual scope as well as its practical boundaries, e.g., regarding freedom of expression or the legitimate role of religious symbols in educational institutions. The contributions to this volume take up a number of carefully selected key questions and problems emerging from these ongoing theoretical and political controversies in order to explore and shed new light on pivotal conflicts and tensions that pervade different conceptions of toleration. The chapters in this book were originally published in the Critical Review of International Social and Political Philosophy.