The essays selected for this volume explore the entire range of issues related to the question of how to implement and enforce international humanitarian law. Measures of self-help that used to play a key role in past international armed conflicts, especially reprisals, have increasingly been outlawed, and thus the enforcement of international humanitarian law has now to be achieved by other means, including criminal proceedings against those who have seriously (or gravely) committed war crimes. Accordingly, the concept of grave breaches, the universality principle and international criminal law are dealt with extensively in this collection. Finally, the volume includes an examination of the practice of ‘lawfare’ (an abuse of international humanitarian law for military or political purposes) which has proven increasingly effective in contemporary armed conflict.