Research on early adolescence reveals significant declines in intrinsic motivation for reading and points out the need for metacognitive strategy use among middle school students. Research indicates that explicit instruction involving motivation and metacognitive support for reading strategy use in the context of a discipline is an efficient and effective means of increasing reading comprehension. Studies also show evidence that reading engagement mediates the relations between instruction and comprehension. The study investigated the effects of explicit strategy instruction in summarizing combined with offering students meaningful choices in the classroom as instructional practices for increasing students' reading engagement and expository text comprehension in social studies. The participants were predominantly African American students from sixth grade using a concurrent embedded mixed methods design. The quantitative portion of the design analyzed the outcomes while the qualitative portion focused upon students' subjective experiences. The three class sections were randomly assigned to one of three conditions: the experimental section received instruction in summarizing and was provided with student choice; the second section received instruction in summarizing alone; the third section was provided with student choice alone. The study's most important result showed how the combination of explicit instruction in summarizing and providing meaningful choices in the classroom produced significant increases in expository text comprehension. Furthermore, posttest reading engagement differences affirmed the importance of choice. Moreover, the partial mediation of reading engagement on expository text comprehension adds to evidence of the importance of including both motivational practices in the classroom and explicit instruction to increase reading outcomes. Lastly, the study presents details on the types of student choice preferences which coincide with reported levels of high engagement. In conclusion, the study demonstrated student increases in expository text comprehension using reading engagement principles altered to focus upon one motivator and one reading strategy in the discipline of social studies. It also provides a new demonstration of flow theory as it relates to social studies instruction. Deliberate classroom interventions, which include student diversity and interests through providing meaningful choices, along with explicit instruction in summarizing, can create a classroom of engaged learners with improved reading comprehension levels. [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.]