Our juvenile justice system is too often overly punitive, inefficient, and outdated—especially given new findings about the immaturity of teen and young adult brains and the resulting behaviors. What should be the juvenile justice system’s goals? What are its most egregious failings? Where does it currently show the best results? How could it be better, and what are the most promising new ideas and strategies for working more fairly and productively with young people who break the law?