The first part of the Bennett Lecture for 1975 is a description of the dissociation of visual perception in the macaque monkey by ablation of area 17 on the one hand, and of areas 18 and 19 on the other. Bilateral removal of area 17, with careful preservation of a great part of areas 18 and 19, and of the inferior pulvinar, resulted in loss of binocular fixation, loss of visual recognition of still objects, and loss of visuosocial behavior such as grimacing and vocalization. There remained excellent visuospatial orientation and reaching for moving peripheral visual targets. Removal of areas 18 and 19, with isolation of area 17 from the remainder of cortex, was accomplished in two animals and left intact the ability to distinguish and sort out still objects by vision, with intact fixation, and visuosocial behavior. Spatial orientation was then easily confused by movement.