"Encourage him to switch," says Jodi Mindell, Ph.D., associate director of the Sleep Disorders Center, Children's Hospital in Philadelphia and author of Sleeping Through the Night: How Infants, Toddlers and Their Parents Can Get a Good Night's Sleep, revised edition (HarperCollins). "At night, keep the lights low, and move slowly when you feed him. Be boring. Make sure he gets bright light in the morning, and keep him as busy as you can during the day. Make noise. Play with him." In other words, during the day, be interesting.