This study explored the use of scaffolded lesson study to develop professional teaching knowledge for problem-based historical inquiry (PBHI). Using mixed methods including extensive classroom observations, the study examined six 4th grade social studies teachers' adoption of problem-based historical inquiry in their classroom teaching following three years of lesson study professional development. Findings suggest lesson study can be used to facilitate the development of professional teaching knowledge for PBHI among elementary teachers though transfer of that knowledge to typical classroom teaching outside of lesson study is fraught with challenges. Findings also suggest that lesson study can contribute to the development of a shared professional knowledge culture that might aid elementary teachers in resisting the marginalization of social studies. The study revealed that lesson study holds promise for helping elementary social studies teachers work through the cultural obstacles they confront when trying to use innovative pedagogy in their classrooms. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]