In recent decades, new international courts and other legal bodies have proliferated as international law has broadened beyond the fields of treaty law and diplomatic relations. This development has not only triggered debate about how authority may be held by institutions beyond the state, but has also thrown into question familiar models of authority found in legal and political philosophy. The essays in this book take a philosophical approach to these developments, debates and questions. In doing so, they seek to clarify the relevant issues underpinning, as well as develop possible solutions to the problem of how legal authority may be constructed beyond the state.