Many problems on this globe cannot be solved by one state alone or by a group of states; they can only be addressed if all states work together. Basis for any cooperative solution are multilateral agreements. Such treaties need to be effective regarding the problem they address, and they need to create a framework where the compliance of parties is controlled. If both aspects are fulfilled, problems can be solved. Gerhard Wotawa compares verification and compliance control systems from key treaties in the areas of arms control and environment. He shows that in both areas, such systems are being developed and improved, but along different pathways and with different institutional settings. The author explains that such differences are not justifiable. Treaties should be negotiated considering not only the best practices in their respective area, but taking into account successes and challenges in the other area, and the overall experience gained so far. The book is intended for students of political sciences and international relations, natural scientists interested in treaty verification, and persons involved in the negotiation and verification of international agreements.