The purpose of this report is: (1) To point out the features of a number of manipulative supplemental resources for history and social studies teachers; and (2) to show how similarly manipulative professional development workshops propagate the distorted content and recommended teaching practices of such materials to teachers and their classrooms, thereby influencing what both teachers and students learn. Although this report can appraise only a limited number of materials and workshops, what is here is alarming enough to underline the need for more systematic examination of supplemental history and social science materials and for rethinking professional development in history and social science as it is now conceived. The following are appended: (1) Standards on Islamic History in World History I in the 2002 Massachusetts History and Social Science Curriculum Framework; (2) Summaries of Classroom Projects Prepared by Massachusetts Teachers at a Professional Development Institute on Islamic History; and (3) Outline of a Lesson on the Wampanoag Prepared by a teacher at a Professional Development Institute for Massachusetts Elementary Teachers.