An examination of the present and future usefulness of systems analysis as an approach to policy planning, particularly in matters of national security. The study considers the basic concepts of systems analysis, including the problem of selecting operationally useful objectives, measures of their attainment, and criteria; the treatment of uncertainty; the place and function of technological considerations in planning or evaluating advanced systems; the character and role of resource and cost-sensitivity analysis; and the nature and value of models in systems analysis, especially the models provided by mathematical game theory, simulation, scenario writing, political analysis, and gaming. Earlier conclusions are reexamined in the light of the successes and failures of systems analysis during the past decade. Newer methods of analysis are discussed.