Feedback such as the above from a recent cohort of Teaching American History grant participants should have inspired my colleagues and me to celebrate our success. Aft er all, one of our explicit goals over the two years we worked with this group of teachers was to introduce them to the historical discipline through the use of primary sources and to encourage them to use documents in their own classrooms. So reports from teachers that they are using primary sources to shape their teaching are indeed gratifying. But eight years of working with TAH grants has taught me that much is lost in the translation from grant activities to lesson design. When I read such comments, I want to know more: What function do primary sources serve in their lessons? To what extent do their lessons develop historical thinking skills? How well do the skills we focus on in grant programs translate into classroom activities that actually transform students’ understanding of continuity and change, context, complexity, cause and eff ect, and contingency? In this chapter, I examine the unit and lesson designs of participants in our grants to consider such questions.