Until recently, few K-12 teachers outside of social studies have integrated primary sources in classroom instruction. Integrating primary sources in educational practice does require an uncommon pedagogical understanding. Addressing this K-12 educator need is the Library of Congress. Recently, the Library implemented a national educator professional development program, Teaching with Primary Sources (TPS). The TPS program operates at multiple universities and colleges, including Loyola University Chicago. This program aims to educate K-12 educators of all subject-areas to integrate online, digitized primary sources into classroom practices. This study addressed questions related to the outcomes of teacher participants' classroom practices after completing a TPS graduate course at Loyola. Results of this study revealed changes in teachers' practices. K-12 teachers of all subject areas, student age groups and ability levels, reported increases in types and frequencies of primary sources used in a given month. Reasons teachers used primary sources were wide ranging. The most common reason reported was for inferential and analytical skill increases, meanwhile, meeting learning standards was least recognized. Teachers' reported classroom practices noted uses of primary sources to: illustrate concepts; provide examples; enhance secondary sources; to assist in student increases in higher order thinking skills; assess formatively and summatively, and cross-subject areas and grade levels. Results showed that hands-on, real-world connections were easily engaging for all student learners and age groups, K-12. Lastly, teachers reported increases in student engagement, motivation and deeper levels of empathic and content learning with primary sources. The TPS graduate course had an impact on teacher practices with primary sources. This study provides evidence that Loyola's TPS course could serve as a national model of best-practice for the TPS program nationally. This study revealed that teachers outside of social studies and below grade four are able to successfully integrate primary sources for increased student learning. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]