"In dermatology, few medications are more important in preventing serious disease than sunscreens. Sunscreens scatter or reflect ultraviolet (UV)-B or -A radiation from the sun. The same sun that gives the earth life, also damages DNA-producing actinic keratoses and causes precancerous growths indicative of mild DNA damage, and basal cell or squamous cell carcinomas, cancerous growths indicative of more severe DNA damage. UV radiation, in addition to other factors, also has been implicated in the most serious form of skin cancer, malignant melanoma. Sunscreens are the most important part of the preventative armamentarium of the dermatologist. Even though sunscreens are not prescription drugs, they do represent important drugs, and demand understanding. It is the goal of this issue to impart that understanding in a concise, thorough manner." From the Preface of this issue.