This issue of Scientific American Mind contains six fascinating articles.In the cover story, "The Teen Brain: Hard at Work. No... Really!", science reveals the ongoing changes underlying adolescent behavior. Next, you'll hear how researchers are achieving amazing results treating severely depressed patients by implanting an electrode in the brain. Then, you'll get some insights into why some people turn violent, and why some faint at the sight of blood. This special issue wraps up with two articles about the workplace: why diversity doesn't always translate into better performance and new ways to spark creativity.