William Dement (1928-2020), US sleep researcher with a polysomnogram printout. Dement was a pioneer of the fields of sleep medicine and sleep research. As a graduate and intern Dement studied rapid eye movement (REM) during sleep and sleep deprivation. He was among the first to use EEG (electroencephalography) to study sleeping subjects. In 1963 he moved to the Stanford School of Medicine, where he studied sleep disorders and in 1970 founded what is believed to be the first sleep disorders clinic, now the Stanford Sleep Medicine Center, in 1970. At Stanford Dement pioneered research into sleep physiology and sleep disorders, including sleep apnoea and narcolepsy, and highlighted the dangers of sleep deprivation and the importance of sleep to health. Photographed at the Stanford Sleep Clinic, Palo Alto, California, USA, in 1987.