Do you know that if you are a black man in urban America you now stand a one in nineteen chance of being murdered? In World War II, the odds of being killed were one in fifty. In New York City there is one murder every four hours. Murder there has become the most common cause of death for people under thirty-five – and yet New York isn’t even the most murderous city in America. At least eight other cities have a higher murder rate. In Los Angeles there are more murders each year on school-grounds alone than there are in the whole of London.