This paper was part of a symposium in which research on Project 100,000 was summarized. The report presents information on three major HumRRO projects concerned with training and performance of men of varying ability levels. The first project compared on-the-job performance of military personnel of varying ability levels. The second project concentrated on literacy requirements for military jobs. The third project concerned developing and testing, in an operational context, instructional programs appropriate for simultaneously training men of various ability levels. (Author)