1. We found no relationship between gross clinical ratings of "ego-integrity" and the production of perceptual aberrations in this experiment.2. Imagery occurs in subjects who habitually have hypnagogic imagery, both healthy and unhealthy. Less healthy subjects are more likely to interact with their imagery in an emotional way due to impared reality testing.3. Sensory deprivation is an ambiguous situation which the subject structures according to his own personality and handles with his habitual adaptive and defensive resources.4. We believe that sensory deprivation does not shed much light on the psychodynamics of personality save for reactions to solitude and loneliness. It does, however, offer unique opportunity for the study of the interrelations of the various components of the perceptual apparatus and for the elucidation of the nature and meaning of hypnagogic imagery. For these studies more careful perceptual measurements and more sensitive techniques permitting greater insight into the relationship of imagery to personality are necessary.