The goal of the study is to develop an equity-minded theory of college writing readiness. An estimated third of incoming students are academically underprepared for college writing. The majority of these students will not earn a baccalaureate. Because rigorous pre-college preparation is a chief indicator of postsecondary achievement, improving college writing preparation in high schools is strategic to increase graduation rates. The writing disparities linked to the prevailing cognitive model of writing instruction raise equity concerns that hinder successful reform to meet the literacy learning needs of students from all linguistic backgrounds. In redress, this study offers qualitative information to assess the conceptual fit of a sociocultural framework--known as new literacies theory--to describe how literacy learning occurred with two groups of students enrolled in high school college preparation. The study employs ethnographic methods to explore how the discourses practiced in college preparation classrooms support college writing readiness across different student groups. New literacies provides the frame for exploring college preparation as it is influenced not only by the local social and cultural patterns instantiated in each classroom, but also by the variant linguistic resources students bring to their respective classrooms. The study's empirical objective is to describe how college preparatory academic rigor is amplified or reduced by students' own classroom language participation. Because how college writing readiness is theorized guides how college preparation is conceptualized in policy and practice, theory development is necessary to support academic writing outcomes (and the postsecondary opportunities these outcomes represent) for all students. [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.]