In recent years, the incidence of violent crime committed by teenagers has escalated, a fact that has hardly escaped the news media. When faced with the challenge of understanding and explaining such occurences in the headlines, one is tempted to rely upon the truism: There are good kids and there are bad kids. Michael D. Kelleher, noted expert on the subject of violence, asserts in When Good Kids Kill that this belief is outdated, oversimplified,...