Is the purpose of exercise just to keep fit and lose weight? Of course not. John Ratey and Eric Hagerman use convincing experimental data and case studies to demonstrate that exercise is a natural brain booster. It not only provides a cure for many diseases but also has a preventative effect. In addition to improving memory and attention deficit disorder, exercise helps us fight off stress and anxiety, balances hormones in women, and will make you less fearful in your struggle against aging.