Desert Elementary is a suburban Phoenix K-5 school. The school has undergone a significant change in its approach to reading instruction due to the Common Core State Standards (CCSS) instructional shift of building knowledge through content rich nonfiction. Teachers implemented this shift in their classrooms through a 16-month professional development program called Students Talking for a Change (STFAC). This qualitative action research study explored how teacher perception of reading instruction was affected by this change in instructional practice. Data collection comprised of classroom observations, teacher interviews, planning artifacts, professional development session artifacts and student work in order to determine teacher understandings about reading comprehension and perception of classroom practice. Prior to the professional development, teachers understood reading comprehension to be answering questions correctly and acquiring skills dictated by a basal reader. The texts teachers once used to teach reading lacked topical coherence. As teachers learned how to integrate content into language arts through long-term planning and sustained exposure to a topic of study, teachers changed their understanding about reading instruction. The perception was that content, discussion and multiple interpretations were central components to comprehension. Further, planning documents evolved from student packets to unit plans based on social studies, science and literature.