JEROME M. SIEGEL is a professor of psychiatry and a member of the Brain Research Institute at the University of California at Los Angeles Medical Center. He is also chief of neurobiology research at the Sepulveda Veterans Affairs Medical Center. He is a former president of the Sleep Research Society and chair of the Associated Professional Sleep Societies. His other research interests include the evolution and function of REM sleep and the effects of sleep deprivation and apnea.