This book discusses the relatively new development of interactive communication or dialog between men and computers. In this mutual exchange of information between two systems, each enjoys some independence of action, and the demand for improved information systems would be alleviated if effective communication between man and machine were resolved to yield better results than either could produce independently. Part I covers the basic aspects of interactive systems: the hardware or mechanical devices, computer programming, time-sharing, and natural language processing; Part II contains basic systems that are fully interactive; and Part III considers a representative set of advanced applications and concludes with a summary of the major problems of man-machine communications systems and a forecast of future developments. (AB)