Some contemporary and psychoanalytic theories of dream function are reviewed. Particular attention is given to Jung's model of personality and theory of dream function, a dynamic, open-system approach that stands in contrast to Freud's mechanistic, drive-reduction model. Contemporary theories tend to focus on the function of environmental mastery, viewed from one of three perspectives: (a) problem solving, (i) information processing, or (c) ego consolidation. Only a few have gone beyond environmental control to consider creative functions of the dream. Most contemporary theories are at least partially supported by data, and many are not mutually exclusive, dealing with different processes or proposing similar processes in different-sou nding languages. Some dream theories do differ from others in underlying model, in scope, or in the degree to which nonrational processes are admissable as data. Jung's approach has much to add to contemporary dream theory, particularly in making room for creative and nonrational processes, as well as in the specific proposition that dreams function to balance and complete waking consciousness. Many answers have been suggested to the question of what function dreams serve in man's psychology. In this century, the most influential theory has been Freud's and his views have given laboratory psychology a fruitful source of hypotheses and debate. The mainstream of American scientific thought in this area has grown directly from laboratory research but is richly sprinkled with Freudian theory together with a Darwinian emphasis on adaptation as environmental mastery. Jung's approach to dream function, very different from Freud's and perhaps more compatible with current research findings, has remained outside the mainstream and is virtually unknown to American psychology. This paper aims to correct the omission, while providing an overview of psychoanalyti c and contemporary thought about the function pf dreams. Freud (1953) believed that dreams serve a dual, compromise function. According to his theory, unconscious, instinctual drive energy pushes for discharge, moving toward the expression of a consciously unacceptable impulse. The reduction in conscious restraints characteristic of sleep permits a symbolic, disguised dream expression of the repressed wish. The 1 Requests for reprints should be sent to Janet O.