This book offers a view of the lives of the world's poorest people, helping to explain why the poor tend to borrow in order to save, why they miss out on free life-saving immunizations but pay for drugs that they do not need, and the cointerintuitive challenges faced by those living on less than 99 cents a day. Billions of government dollars, and thousands of charitable organizations and NGOs, are dedicated to helping the world's poor. But much of...