Understanding computer technology as it is designed for and used in the workplace requires analysis of organisations, the labour process, and technology in general. While some outstanding work has been done on how technology and organisations interact during implementation, there is still a need for further development of a dynamic model of the social process of technology creation and use. This chapter outlines some of the important elements for -such a model developed from empirical analysis of the development and use of mission-critical software systems. (An extended account of this research and analysis appears in Software By Design: Shaping Technology and the Workplace, Salzman and Rosenthal, 1994).