Project-based product development often necessitates cross-functional cooperation, involving the simultaneous development of various local knowledge bases and ways of integrating these in bringing about a product or a service, mirroring a coherent conception of a new product idea, a new technological solution, etc. However, as reported in the literature, it is not uncommon that such endeavours result in malfunctioning products, products finished at too high a cost, too late, etc. One recurrent explanation is that cooperate efforts fail due to the fact that the participants have different background knowledge, do not speak the same "language" and the like. In the light of the above description, the general ambition in this research project is to contribute to our knowledge about what kind of problem-solving is going on in product development projects. In particular, the aim is to investigate how boundary conditions between different specialties involved in cross-functional work, may be handled. What obstacles, tools and solutions may we identify? Theoretically, this project will try to connect the literature on sociology of science with that of project organization. Empirically, it will include case studies relying on qualitative methodology.