This thesis investigates the challenges within the work of different types of professions; technical professions and human caretaking professions. These professions are faced special challenges in use and development of information systems. Professions within two different complex and critical work practices are focused; aircraft maintenance and emergency medical care. Within the work of these professions some judgements and decisions can imply risks for life and equipment. The use and development of information systems in general is emphasised, decision support systems and other systems for specific tasks have not been studied. The research question in this thesis is:

Which challenges can be related to use and development of information systems within complex and critical work practices, from a profession-oriented perspective?

Two ethnographical studies have been performed within two different work practices. The studies have been rather explorative and inductive. One study has been performed within the aircraft maintenance in the Swedish Airforce and the other study has been performed within the emergency medical care within NU Healthcare, Västra Götaland, Sweden.

From the thesis it has been derived three main challenges for professions within complex and critical work practices; trust, knowledge integration and professional barriers. The main contribution in the thesis is about certain aspects, which can have an impact on a profession-oriented view on use and development of information systems. These aspects concern bridging professional barriers and managing knowledge integration. Furthermore the thesis reflects that a hard systems thinking on use and development of information systems is prevalent within the human caretaking professions, while a soft systems thinking is obvious within the technical professions.