Sensory deprivation has been produced experimentally by reducing the absolute intensity of stimuli, by reducing the patterning of stimuli, and by imposing a structuring of stimuli. Explorers have experienced it voluntarily and prisoners have had it thrust upon them.While there are many separate factors operating in these various situations, it is clear that the stability of man's mental state is dependent on adequate perceptual contact with the outside world. Observations have shown the following common features in cases of sensory deprivation: intense desire for extrinsic sensory stimuli and bodily motion, increased suggestibility, impairment of organized thinking, oppression and depression, and, in extreme cases, hallucinations, delusions, and confusion.Though the basic concepts regarding perceptual and sensory deprivation are not new, their recent importance in experimental and real life situations has made them increasingly interesting. Future studies in this area may well contribute to our knowledge of the psychological and behavioral patterns of man under conditions of normality and stress.Abstract Teaser