This paper examines situations for which nonlethal weapons are appropriate and limitations on the use of such weapons. Weapons in research and development are reviewed, along with some new concepts and proposals. Research recommendations are made. This work was accomplished in the period October, 1966 through January, 1967. In each category the physical or physiological basis for operation of the weapon, and the intrinsic limitations on its development or use, are discussed. The emphasis is on the need for a systematic program of research and development which includes problem analysis, determination of objectives, research, test and evaluation, reportage and training.