History and Basics. The History of Human Photobiology. Basic Principles of Photobiology. Radiation Sources and Interaction with Skin. Effects of Ultraviolet Radiation on Normal Skin. The Molecular and Genetic Effects of Ultraviolet Radiation Exposure on Skin Cells. Photoimmunology. The Acute Effects of Ultraviolet Radiation on the Skin. The Chronic Effects of Ultraviolet Radiation on the Skin: Photoaging. The Chronic Effects of Ultraviolet Radiation on the Skin: Photocarcinogenesis. The Epidemiology of Skin Cancer. Photodermatoses. Basic Principles. Evaluation of the Photosensitive Patients. Immunologically Mediated Photodermatoses. Polymorphic Light Eruption, Actinic Prurigo and Hydroa Vacciniforme. Chronic Actinic Dermatitis. Solar Urticaria. Drug and Chemical-Induced Photosensitivity. Drug and Chemical Photosensitivity: Exogenous. Drug and Chemical Photosensitivity: Endogenous: The Cutaneous Porphyrias. DNA Repair-Deficient Photodermatoses. Xeroderma Pigmentosum and the Other DNA Repair-Deficient Photodermatoses. Photoaggravated Dermatoses. The Photoaggravated Dermatoses. Photoprotection. Photoprotection. Novel Developments in Photoprotection. Public education in Photoprotection. Ultraviolet and Visible Radiation Therapy. Phototherapy with UVB, Broadband and Narrowband. UVA1 and Visible Light Phototherapy. Psoralen Photochemotherapy. Extracorporeal Photochemotherapy. Photodynamic Therapy. The Principles and Medical Applications of Lasers and Similar Radiation Sources in Dermatology. The Cosmetic Applications of Lasers and Similar Radiation Sources in Dermatology. Laser in People of Color. Appendices