Read: Doug Saunders - Arrival City, the Final Migration and our Next World

Great book. Humans are progressively becoming an urban species, and it's a good thing - higher standards of living, lower birth rates, more energy-efficient all around. But the transition process can be messy, resulting in slums. Doug Saunders' argument, bolstered by a tremendous amount of personal stories from people he has met and interviewed, is that slums aren't all they seem on quick glance - if all is working as it should, residents are moving in and up out of them within a generation, so that poverty doesn't become entrenched. Property ownership and the opportunity to set up small businesses easily are the key to keeping the system moving.