Photophysiology: Current Topics, Volume IV focuses on various topics in photophysiology, including photochemistry, pyridine nucleotide-linked systems, and bioluminescence. The selection first elaborates on photochemistry and vision, photoperiodism in insects, and response of human skin to ultraviolet light. Discussions focus on clinical photopathology, chronic effects of ultraviolet radiation on human skin, optics of the skin, spectral sensitivity, interaction of photoperiod with other environmental variables, effects of high-intensity radiation, human cone pigments, and effect of light. The text then ponders on cellular recovery from photochemical damage and a physical approach to bioluminescence. Concerns cover theoretical background for excited states, results and interpretation of mechanism, biological consequences of photochemical events, reconstruction of damaged DNA, and physiological and environmental effects on repair and recovery. The book takes a look at the enzymic aspects of bioluminescence, including pyridine nucleotide-linked systems, peroxidation systems, and simple enzyme-substrate systems. The selection is a dependable reference for researchers wanting to study photophysiology.