DESCRIPTION: Paperback book. Why is it so satisfying to walk up and downstairs? Maybe it's the new layer of discovery with each step up—a new far-off view and a new close-up look at the plants and buildings. Maybe it's the fleeting proximity one has to passing strangers. Maybe it's the great feeling of propelling yourself upward and then floating downward. Maybe it's the best workout you can get without putting on gym clothes.