One commonly stated instructor goal for an introductory calculus-based physics course is to improve students' problem solving skills. There is, however, a growing body of research evidence to suggest that this goal is not frequently accomplished in a typical college or university physics course. In response to this evidence, researchers and curriculum developers have developed a wide variety of curricular materials and instructional strategies that have been shown to be more effective in improving student problem solving performance. In spite of the availability of these curricular materials and instructional strategies, relatively few physics instructors have chosen to use them. One likely reason is that these curricular materials and instructional strategies do not align with, and perhaps are in conflict with, the ways that physics instructors think about the teaching and learning of problem solving. This has led the Physics Education Research and Development Group at the University of Minnesota to undertake a long-term, multistage research program to understand physics instructors' conceptions about the teaching and learning of problem solving.