This chapter deals with IT design in an organizational setting – be it a medium sized service company, a large industrial company, a small entrepreneurial knowledge company, or a public company or institution. In such work settings we often find a complex organizational structure, including several management levels, diverse professional groups, workplace cultures, and established working relations where new IT projects challenge the established ways-of-working. This is also the domain of "classic' information systems development (ISD) approaches. This chapter presents the principles, key ideas, and experiences from using the participatory design method known as the "MUST method', developed by the authors (Bødker et al. 2004).