Operations research is a novel approach to the problem of making sound decisions in complex matters. Conceived during the last war by scientists helping the war effort, it has proved its usefulness in many fields, as different as hunting enemy submarines and determining optimal rates of industrial production. Very briefly, the operations research approach consists in determining one's objectives, selecting meaningful measures of achievement, formulating a mathematical model of the problem to show both the variables under control and those not subject to control, and indicating the results of alternate courses of action (2). Problems of roentgen diagnosis are many, but they do not greatly resemble those of finding hidden submersibles, except for the trying necessity of making important decisions when information available is incomplete or uncertain. The art of diagnosis is the art of evaluating equivocal evidence. Problems of patients with partial proof provide the pitfalls and pleasures of roentgen iconog...