The different contributions assembled in this volume clearly bring out the complexity and sophistication of treaty regimes aimed at securing the observance of rules of international law in the fields of human rights law, international environmental law and arms control law. It is not possible, in the space of this short comment, to assess the different contributions in any detail. However, some general perspectives on the role of enforcement within the process of securing compliance with international law may be offered. More specifically, three points will be covered. First, the contributions prompt a number of remarks about issues of terminology and about the basic features of the concept of ‘enforcement’. Secondly, and most importantly, on the basis of the distinctions thus introduced, this comment will briefly review the different enforcement strategies pursued in the fields of human rights law, international environmental law and arms control law. And, lastly, it may be fruitful to reflect about the specific features of the three fields of law from the perspective of the general law of State responsibility, as elaborated by the UN International Law Commission in its Articles on State Responsibility, adopted after second reading in August 2001. Terminology and basic distinctions It seems necessary to begin by seeking to define what is meant by ‘enforcement’.