Working under an activity theory framework, the present study was designed to determine how the activity settings, individual and contextual, contributed to the instructional practices and understandings of test-only beginning special education teachers. Specifically, the focus of this study was to examine how teachers with no formal teacher education preparation use and appropriate curriculum to develop, implement, and learn about reading instruction. To understand the influence of the activity systems in general and more specifically, curriculum, on special education teacher appropriation of conceptual and practical tools grounded theory methods were used. Three special education teachers entering the classroom through the test-only route, who taught reading to struggling readers and students with disabilities, participated in the study. The data sources consisted of participant interviews, observations, the Reading in Special Education (RISE) observation instrument, the Pathwise observation instrument, pre-concept maps, and additional instructional artifacts. Grounded within the data on test-only teacher appropriation of conceptual and practical tools, a theory emerged from three analysis phases (i.e., open, axial, and selective coding). In summary, three test-only beginners were all affected by the level of access to curricular supports. These curricular supports worked as both a catalyst and mediator for activity system influences ultimately impacting instructional practice, teacher understandings, and interaction with other activity systems factors. Beginners with no previous preparation in reading instruction, with the aid of curricular supports (i.e., structured curriculum, mentoring around the curriculum, modeling instruction using curriculum) were able to enact and develop an understanding of both general instructional practices and fundamental reading components. [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/en-US/products/dissertations/individuals.shtml.]