Reviews progress toward the development of a cognitive theory of aptitude for learning and presents descriptive and prescriptive goals for aptitude theories. Preliminary hypotheses about the nature of cognitive processes in aptitude for learning from instruction are reviewed. 12 constituent points of the descriptive theory are presented. Some of these points are summary conclusions on much prior research, whereas others are less well supported at present. However, all contribute to the effort to describe learning and aptitude for learning in conformable terms. Some prescriptive implications of the theory, intended as hypotheses for instructional development and design research in particular locations, are also discussed. (102 ref)