The last chapter of Collier's excellent and readable book, is called Changing Reality. And that is what really matters. Can his prescriptions for stopping wars and allowing development to take place in the world's poorest and most unstable countries be turned into reality? I believe so. Not least if enough people - including some big cheeses as suggested in another review - read it. The proposal that war and guns are one of the main causes of global poverty is not so new - though it is excellent to see it analysed as thoroughly as Collier does here. The question is what to do about it. In recent years, the answers have all been about building up the capacity to stop wars and conflicts. And the debate has been about whether the African Union could do this, or the UN? Or would it take NATO or the USA? What Collier does is refocus the debate on preventing wars, not ending them. Normally, preventing wars leads to discussions of arms control. And Collier discusses that here. But he's realistic about what can be done along porous borders, and so he looks for other ways too. His big solution is the "security guarantee": If a credible outside force says that it will intervene to stop any attempted coup, then many of the wars we have seen could be prevented. Preventing wars of course costs less lives and less money than ending them - though results in fewer medals. The question which Collier leaves us with, is whether we would be prepared for our armed forces to provide that guarantee. Given current actions in Afghanistan, that is a tough question for our society. But Collier has some tough answers as to why it really would be worth it. If you doubt it, keep your mind open and read the book.