Abstract Requirements of the personal computer user are identified and contrasted with computer designer perspectives towards the user. The user's psychological needs are described so that the design of the user-computer interface may be designed to accommodate them. Development of the user-computer interface is discussed in terms of the user's physical, perceptual and conceptual contact with the system. The ideals of system transparency and visibility to the user are described resulting in a set of dialogue principles. Further research is suggested which will explore the characteristics of efficacious menu selection, develop a theory of the operator, determine the best locus of control for dialogue features. provide guidelines for improving system documentation and improve user work station habitability.