This text documents the science that lies behind the expanding field of cosmetic dermatology so that clinicians can practice with confidence and researchers can be fully aware of the clinical implications of their work. New chapters have been added to this edition on photodamage, actinic keratoses, UV lamps, hidradenitis suppurativa, age-related changes in male skin, changes in female hair with aging, nonabltaive laser rejuvenation, and cryolipolysis, and chapters have been updated throughout to keep this at the forefront of work and practice.