This volume collects six original essays by internationally respected researchers who have devoted themselves to the study of legal obligation. It brings together works that innovatively address key dimensions of the current debates concerning legal obligation from different and, in some cases, even opposing theoretical perspectives. As a result, the collection offers a comprehensive discussion of legal obligation that promises to significantly advance our understanding of the obligatory dimension of law. What specifically connects the contributions gathered here is one common thread: coming to terms with a notion - legal obligation - that is of both practical and theoretical importance. On the one hand, it is widely regarded as a fundamental legal concept by legal practitioners and laypeople alike, as not only judges, prosecutors, lawyers, and juries but also ordinary citizens make extensive use of obligation-related terms and discourses. On the other hand, the notion of legal obligation is of paramount significance for the theory of law. Indeed, even legal theorists who, quite understandably, refuse to reduce the law to a mere obligation-imposing device and opt instead for a view in which the normative dimension of the law also encompasses powers, rights, permissions, privileges and immunities, duly acknowledge the centrality of legal obligation for the understanding and conceptualisation of law. Hence the importance of the treatments presented in this volume.