At heart, this book is inspired by a willingness to see more to life than money. Trade is a money-making exercise. The statistics show that trade liberalisation, the WTO's leitmotif, does increase welfare. The WTO is ‘good for you’. This cannot be, and has not been, stressed enough. Even if the WTO undoubtedly needs improvement, it would be disastrous to turn back the clock and revert to escalating protectionism. Trade be- tween nations makes the world a better place. It also makes it a safer place. But at the same time, trade is but an instrument to achieve nobler goals: the prevention of war; raising standards of living and the creation of jobs, not just in the rich countries but also in the developing world; political freedom and respect for human rights; social protection and an equitable distribution of wealth; the fight against environmental degradation and the protection of public health; etc. Given the diversity of WTO members, these goals must, in the first place, be set by each member individually, preferably, of course, in co-operation with other members. When genuinely pursued, that is, when not abused as a dis- guised restriction on trade, such goals must trump the instrument of trade, even if they are not set out in the WTO treaty itself. This should be particularly so in case these goals have been defined in other, non-WTO rules of international law as between WTO members that have agreed to those rules. WTO law is not a secluded island but part of the territorial domain of international law. The WTO, important as it may be, must thus be put in perspective. For public international law at large, this ap- proach pleads for the unity of international law, not its fragmentation. However, to achieve this unitary view, rules must be developed on how norms of international law interact. This is what this study attempts to do.