This three-part article begins with a brief presentation of a framework that describes different approaches to conduct and report research on expert knowledge. The framework contrasts "direct vs. indirect" approaches and provides examples of each. Second, the article gives a detailed description of the methods and results of three concept mapping studies in pulmonary physiology that employ Pathfinder scaling, an "indirect" approach. The studies derive concepts maps for a variety of faculty experts individually and in groups. Two of the studies focus on changes in students' concept maps of the pulmonary physiology concepts as a result of instruction. Changes are gauged in terms of the degree to which students' concept maps approximate instructors' concept maps due to educational interventions. An index of student-instructor concept map similarity is also correlated with student performance on final examinations. The article concludes by articulating several "next steps" in the Feinberg Northwestern and Wisconsin program of health sciences education research on concept mapping using Pathfinder scaling.