A winner of the National Book Award and the Pulitzer Prize, Tina Rosenberg has spent her career tackling some of the world's hardest problems. Now, through striking stories from around the globe, Rosenberg shows how positive peer pressure can change people's behavior and solve seemingly intractable social quandaries. In every case, pioneering social entrepreneurs throw out the old models for social change in favor of humanity's most powerful and abundant resource: our connections with one another. The result is one of those rare books that will not only revolutionize the way you look at the world but also give you the power to change it.