As providers of professional development opportunities for educators envision what they do, there is strong evidence that productive and effective opportunities should include the following: active learning, authentic professional practice, challenging of assumptions, coherence, collective participation, content focus, duration, learning from participant's own practice, and opportunities for critical refection (Desimone, 2009; Smith, 2010; Webster-Wright, 2009). In the development and facilitation of the Teaching with Primary Sources program, the Library of Congress has incorporated these elements to create a cohesive, collaborative, and engaging model for Professional Learning. To date, tens of thousands of educators have been exposed to the TPS curriculum provided by Library of Congress staff, Consortium members from 17 states throughout the United States, and regional grantees found within all 50 states and the District of Columbia.