The Science of Reading era has (re)ignited conversations about equitable literacy instruction. Conflicting literacy research and literacy media reports complicate matters further. Guided reading, a ubiquitous form of small group instruction designed to meet readers' needs through individualized conferring and independent reading with instructional-leveled texts, has been under scrutiny and needs more research. This case study investigated guided reading in a third-grade classroom and explored how the classroom community co-constructed reading and the reading process. Theoretically framed by social constructivism, psycholinguistics, socio-psycholinguistics, and sociolinguistics, this ethnographic-informed case study of n=1 third-grade teacher and n=17 students revealed adherences to and deviations from recommended guided reading instruction. The teacher's guided reading enactment was influenced by imperfect professional development and past reading experiences. This led to enacted adherences (schema building before reading, independent reading during reading, text discussions after reading) and deviations (round-robin reading and absence of conferring). These findings suggest value in identifying nonnegotiables of guided reading and possible negotiable elements in deference to teacher agency. Additionally, an examination of reading and the reading process as cultural constructions yielded a set of norms, such as "reading is about the words" and "reading is not an attention sustaining act" that revealed discrepancies between stated values and co-constructed culture. Implications for practice include shifting from expecting a teacher to be a master of reading to instead embracing a reading-in-process stance; and offering professional development that encourages the interrogation of literacy ideologies. Implications for researchers include the need for observational data to report nuanced (mis)understandings and illuminate the complexities of enacting guided reading as well as other complex teaching models. Further research is needed to understand why deviations to practice occur and the ways actual classroom communities culturally co-construct reading and the reading process. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]