ideology, ignorance, and inertia—the three I’s—on the part of the expert, the aid worker, or the local policy maker, often explain why policies fail and why aid does not have the effect it should. It is possible to make the world a better place—probably not tomorrow, but in some future that is within our reach—but we cannot get there with lazy thinking. We hope to persuade you that our patient, step-by-step approach is not only a more effective way to fight poverty, but also one that makes the world a more interesting place.