Book excerpt: Exercising your brain is just as important as working out. If you don't exercise your brain, it will atrophy, at least the part your not using. 'Use it or lose it' is as true of our mental faculties as it is of our physical abilities. Fortunately, most of us do get plenty of stimulation in our daily lives, jobs, leisure activities and relationships. The problem is that our brain stimulation is often not very balanced, and that imbalance can affect your sense of well-being. This book provides exercises for all the major brain functions at several different levels. Inside you will be able to: test your brain fitness level, develop right brain association and creative ability, and improve your logic and numbers skills using left-brain workouts invented by scientists.