This series in diagnostic radiological physics has been designed to provide the physics background requisite for the proper conduct of medical diagnostic x-ray examinations. The basic goal of the series is to bridge physics theory and radiological practice, achieved by combining pertinent lecture material with laboratory exercises that illustrate the clinical applications under simulated clinical conditions. Nine chapters contain background physics information and laboratory exercises on the following topics: (1) x-ray production and machine output; (2) radiographic contrast; (3) subject contrast; (4) the control of scattered radiation; (5) intensifying screens; (6) radiographic film; (7) contrast and processing; (8) quality assurance of automatic film processing; (9) geometric factors in radiography; (10) x-ray quality assurance; and (11) reduction of unnecessary patient exposure. (CS)