Decodable books based on previous classroom instruction are the most frequently used texts for 1st grade reading instruction in public schools, yet no empirical studies exist demonstrating their efficacy or their benefits for beginning readers. This study attempts to address this gap in the research literature by analyzing the reading behaviors of a group of 1st grade students reading the decodable texts included as part of the 1st grade reading curriculum in a large public, urban school district. Students read the 24 texts sampled in this study over the course of five months and detailed analysis of their reading behavior demonstrated the differential effects of these texts on high-performing, mid-performing and low-performing readers. High-performing readers began the year reading beyond the level of the decodable texts and interacted with the decodable texts minimally. Mid-performing students clearly benefited from reading the decodable texts even though their accuracy and fluency scores indicated substantial difficulties with the texts. For struggling beginning readers, however, the decodable texts were too difficult and the consistently low accuracy and low fluency scores were coupled with a range of problematic reading behaviors that demonstrated the disproportionate difficulty struggling readers had with the decodable texts. [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.]