In 1984, Dr. Norman Rosenthal and his colleagues published a seminal research paper on seasonal affective disorder (SAD), unveiling what they were convinced was the healing power of light therapy for people suffering from the illness. This wide-ranging book combines in a single, cohesive reference new findings with a complete summary of the available literature on light therapy. Seventeen contributors, leading clinicians studying the effects and uses of light treatment, discuss the impact of light and light therapy on conditions such as SAD, premenstrual depression, circadian phase sleep disorders, jet lag, shift work disorders, insomnia, and behavioral disturbances.