In the early 1990s a young Englishman walked up the steep mountainside that surrounds Rio de Janeiro and into a favela, a slum unlike anything seen in the United States. It was a place ruled by drug gangs and the daily scene of murders and gun fights between the inhabitants and the police. He walked in and began talking to some kids about what was happening in their lives. Nearly 20 years later, the justice and educational systems of Brazil have been altered, and the work he started there has spread around the world. As I write this I am in Champaign-Urbana, Ill., a 12-hour-drive from my home in Kennesaw, Ga.