Managers are universally regarded as key to the fortunes of organizations, yet there has been little focus on the effects of information technology (I.T.) on this group. In this research, the implications of I.T. for the work and roles of managers were studied, permanently in office settings, in five manufacturing companies in the Northern Home Counties. The cases provided a wide range of both organizational cultures and I.T. use. Data were obtained largely through 101 semistructured interviews with managers in various hierarchical and functional positions. Supporting material came from questionnaires and documents. and through informal observation on the 49 visits to companies. I.T. consists of several interwoven and rapidly developing computing and communications technologies, and is interacting with the extremely varied environments found in the companies. There is no revolution. Rather I.T. use is growing from its precursors - telex, punched-card machines and earlier computers, and is conditioned powerfully by existing cultures. Gradually, however, the inherent character of the technology is changing practices in general, and management work in particular, in radical ways. The fundamental nature of managers' work is little altered by I.T. It remains fragmented; weakly defined; oral; action orientated. Increased productivity and reduced numbers of staff are consequences of I.T., and these, together with the increase in conceptual and systems skills amongst the work-force, are reducing the hierarchical-authority model of people management, and creating a more "professional-team" culture. The increasing effectiveness of information management that I.T. confers is producing other major consequences for managers. Information management is becoming a central component of their work. Overall, managers are having to adapt to increasingly technological systematised environments, with smaller, more skilled staff teams. The transitions for managers are difficult. especially as companies have given slight attention to preparing managers for these changes, or indeed to management development in general.