Currently, we are measuring the effects of bleaching and background adaptation on intensity discrimination in the rod system. In particular, we are measuring flashed-background increment-threshold functions (1) at various times during dark adaptation following full bleaches, (2) in the presence of steady adapting backgrounds, and (3) in the presence of adapting backgrounds that are extinguished during presentation of flashed backgrounds. Following these experiments we plan to begin examining the effects of bleaches and backgrounds on the apparent brightness of lights in the cone system. These experiments will employ an interocular brightness matching procedure. In addition, we also plan to begin examining the effects of background adaptation in spatial vision. These experiments will involve measuring the sensitization effect (of Westheimer and others) with and without control for local retinal adaptation. All of these experiments will add considerably to the body of data we have collected over the last several years on visual adaptation. We have made considerable progress on developing a general theory of visual adaptation and detection and this progress should continue during the present year.