Over the last few years there has been a flurry of activity in the study of the mechanical design process. This has been fostered by a perceived lack of efficiency and resulting quality in U.S. product designs compared with those of the Japanese and the Europeans. Research activity is broad and has varied over areas as diverse as: the development of computer codes using AI techniques to solve specific problems requiring expertise in a narrow domain; the commercialization of general, parametric design tools; and the modeling of the human cognitive design process. As results have been published, it has become obvious that the term “design” means different things to different researchers. The field is mature enough to allow techniques and results to be classified, compared and contrasted. However, this is difficult because there is no agreed upon description of the types of design and design studies. In other words, there is a need for a taxonomy to characterize the mechanical design process and the research on it.