This report is a review of the literature that might aid in measuring or describing complex images as stimuli, in relating this variable to the psychophysics of target identification, and in further specifying variables that may be important determinants of target identifiability. The body of this report is in four sections: (1) abstracts of articles containing general perceptual material, especially theories of form recognition or target identification; (2) abstracts of articles concerned with the experimental manipulation of perceptual variables known to be important determiners of form recognition and target identification; (3) articles concerned with measuring, changing, or simulating image parameters in some specified manner; and (4) abstracts of articles on the special characteristics of various sensor systems that will affect the resulting images used by the operator.