John Ratey, M.D. is a clinical professor of psychiatry at Harvard Medical School. He is the author of numerous bestselling and groundbreaking books, including Driven to Distraction and A User's Guide to the Brain. He lives in Cambridge, Massachusetts, where he has a private practice. Eric Hagerman is a former editor of Popular Science and Outside. His work has been featured in The Best American Sports Writing 2004, Men's Journal, and PLAY.