Cosmetics for skin, hair, and nails play a vital part in the management and treatment of many dermatological conditions; unfortunately, they may also at times be the cause of some dermatological problems. Dermatologists need to have a working knowledge of over-the-counter products to answer patient questions, make product recommendations to prevent disease recurrence, select products useful in disease maintenance, and enhance appearance. This text bridges the worlds of skin, hair, and nail care formulation, chemistry, ingredients, function, and utility for the physician.