Oneirology is the scientific study of dreams, a relatively new field. The term comes from the Greek Oneiro which means dream.
The discipline is generally agreed to have begun with the discovery by Nathaniel Kleitman and his student Eugene Aserinsky in 1955 of regular cycles in human sleep, in the sleep laboratory at the University of Chicago.
A further experiment by Kleitman and William C. Dement, then another medical student, demonstrated the particular period of sleep in which electrical brain activity as measured by an electroencephalograph (EEG) closely resembled that of waking as the eyes darted about actively. This kind of sleep became known as rapid eye movement (REM) sleep, and Kleitman and Dement's experiment found a correlation of .80 between REM sleep and dreaming.
Oneirology has greatly expanded since these humble beginnings. The independent and almost simultaneous confirmation of lucid dreaming by Stephen LaBerge and Keith Hearne has allowed for many different types of further experiments and developments.