This study of the computer/user interface investigated the role of the computer in performing information tasks that users now perform without computer assistance. Users' perceptual/cognitive processes are to be accelerated or augmented by the computer; a long term goal is to delegate information tasks entirely to the computer. Cybernetic and psychological theories help to identify twelve perceptual/cognitive processes that underlie information tasks: scanning, fixating, feature extracting, decoding, comparing, deciding, inducing, deducing, retrieving, selecting, transforming, and producing. Functions that the computer may perform to accelerate, augment, and delegate these processes are exemplified by displaying, analyzing, simulating, and editing. In the late 1970's, computer research and development can increasingly shift from system-oriented problems to user-oriented problems. The communication functions shared by most users are displaying, commanding, inputting, editing, outputting, and transmitting. It is neither necessary nor desirable that totally new information systems be designed to accommodate these functions. Four types of existing systems (information storage and retrieval, teleconference, instruction, decision support) should be regarded as extendable with respect to new functions. Since existing systems permit low-cost evaluation of new functions, the sequel to this study should be a program of acceleration, augmentation and delegation experiments using existing systems. (Author/JAB)