Co-author Manning Rubin is your “personal trainer,” providing lively narration to guide you through the exercises.

Drawing on cutting-edge neurological research, here is a regimen of mental cross-training—neurobics—that can be done anywhere, by anyone, at any time of day. The premise is simple: When you exercise the brain, you release natural growth factors called neurotrophins, which in turn enhance the brain’s level of fitness. And nothing so easily stimulates the brain as breaking routines and using the five senses in new and unexpected ways. So if you're right-handed, wake up tomorrow and brush your teeth with your left hand. Or close your eyes before you get into the car and then get the key into the ignition. Every time you open a new circuit in your brain, it's like doing a round of mental sit-ups—without the pain.