Nathaniel Kleitman (April 26, 1895 – August 13, 1999)[1][2] was an American physiologist and sleep researcher who served as Professor Emeritus in Physiology at the University of Chicago.
An early sponsor of Kleitman's sleep research was the Wander Company, which manufactured Ovaltine and hoped to promote it as a remedy for insomnia.
Eugene Aserinsky, one of Kleitman's graduate students, decided to hook sleepers up to an early version of an electroencephalogram machine, which scribbled across 1⁄2 mile (800 m) of paper each night.
Another of Kleitman's graduate students, William C. Dement, who was a professor of psychiatry at the Stanford medical school, described this as the year that "the study of sleep became a true scientific field."
Kleitman made countless additional contributions to the field of sleep research and was especially interested in "rest-activity" cycles, leading to many fundamental findings on circadian and ultradian rhythms.