This book focuses on the interrelationship of social, technical, and organizational aspects of and related to the product development process. It originated from activities in practice in industry and research laboratories. In order to ensure relative autonomy from the short-term economic interests of a given industrial branch or specific company, the research for this work was first conducted in pursuit of a PhD thesis intended to provide practice-oriented results. With the ansatz practice – theory – practice, a generalizable approach was achieved. It then evolved to cover additional issues brought forth by recent cases in the aerospace industry, among others. A combination of scientific methodologies is used to focus on the psychological factors that influence the quality of technical product development processes. The basic framework is provided by the grounded theory-a qualitative approach, in which data was not only collected by this author but is extended to cases from the history of technology described in the published literature. The inclusion of historical cases is possible, thanks to the availability of sufficiently detailed descriptions for examination in terms of the grounded theory principles. They appear in the Appendix. Cases cited were verified by comparing them with contrasting viewpoints from various sources. I was able to examine and complement some cases by contacting persons associated with the programs analyzed. Quantitative studies are also integrated in this research to verify the elements resulting from the grounded theory integration.