International law has recently emerged as a thriving field of philosophical inquiry. This volume contains twenty-nine cutting-edge essays by thirty-three leading philosophers and international lawyers. An introduction co-authored by the two editors sets the scene by identifying the value of developing the philosophy of international law, addressing some of the main challenges it confronts, and presenting the aims of the volume together with a brief summary of the essays included in it. The ultimate goal is to help shape an agenda for future research in a burgeoning field