In the first chapter, the author explains his interest in computer-based information systems combined with their interactions with and use by members of the professions, as an on-going research focus and topic. After basic definitions, the discussion moves to the professions that are considered in the thesis and the organisational contexts in which their interactions with information systems occur. Finally, the chapter considers (1) the relevance of dissemination of research results as an integral and essential part of the research process and (2) the author's value framework, within which the studies described in the thesis are presented. The following chapter contains a review of research approaches employed in information systems and software engineering research. These approaches are examined to indicate how and where they have been used in the studies presented in the author's published papers reprinted in chapters three to nine. Because of the predominance of the action research perspective taken by the author, the rationale and results that can be achieved from the action research approach are specifically examined. Finally, chapter two considers the advantages of problem-driven research and the need for a diverse range of research approaches in information systems research. The following seven chapters are reprinted copies of published papers, four from journals and three from conferences. Chapter 3 describes a management problem related to ancillary works of the Thames Barrier; chapter 4 describes optimisation techniques and minimum cost design as used by engineers; chapter 5 describes an accountant's management information system; chapter 6 describes a knowledge-based system related to the selection of pacemakers for a cardiologist; chapter 7 relates to education of engineers in mid-career; and chapters 8 and 9 relate to the education of medical students and doctors in mid-career. The final chapter, chapter 10, reflects on the work described in the earlier chapters; and on factors which might have affected the outcomes of the research. These factors include (1) the role of the author who for periods operated as a consultant-researcher, and (2) the fact that the studies were undertaken in organisations and situations in which a managerialist climate existed. This is followed by research conclusions and implications for future research.