As the content knowledge of the world grows, so do the demands placed upon our educational system. These demands come from a variety of sources--local, state, national, and corporate agencies. Critical to meeting these demands are the knowledge, skills, and practices teachers need to educate today's youth. Researchers in the area of teachers' thinking and reflection have worked to construct a realistic portrayal of teaching, including teachers' thinking, reflection, and planning. However, little research exists on how these three activities work together as teachers seek to implement standards-based instruction. The purpose of this qualitative study was to document the thinking and planning processes of two elementary school teachers (one from grade 4 and the other from grade 5) as they aligned "Common Core State Standards for English Language Arts and Literacy in History/Social Studies, Science, and Technical Subjects" to their social studies teaching. Using case study methods, the study examined how the teachers planned curriculum and moved it into practice, how they understood their actions as they reflected on their practices, and how their reflections affected future planning. Interviews, observations, field notes, audio reflections, and teacher supplied artifacts were analyzed for patterns of thought and practice to offer insight into the two teachers' thinking as each selected and aligned standards to instruction. Findings from the study revealed that educators need to understand: (1) how to read standards statements, (2) how to integrate standards across discipline areas, (3) how to develop meaningful lessons and assessments of student learning, and (4) how to foster the knowledge and skills students need to demonstrate competency. By fostering ongoing teacher learning and reflection, researchers and school leaders can contribute to the knowledgeable, meaningful, and flexible use of standards by teachers to help students learn key concepts within specific discipline areas. [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.]