This dissertation is based on a year and a half multi-institutional study of seven Mexican American students transitioning from high school to a community college or a university. It explores the differences between high school, community college, and university literacy environments, focusing on the following: the impact of standardized testing at the high school level, the role of rhetoric and composition disciplinary expertise in shaping first-year composition (FYC) curricula, writing in the disciplines, and the digital divide between institutions. Seven case studies examine students' literacy experiences across institutions as well as both challenges and sources of support in and beyond the classroom. Drawing on Bourdieu's analytical tools of habitus, capital, and field as well as Yosso's (2005) theory of community cultural wealth, the discussion explores how students formed robust networks of capital to facilitate successful transitions to college and argues that institutions need to undergo dramatic transformations to effectively serve increasingly diverse student populations. The findings have implications not only for writing teachers and scholars, but also teachers in other disciplines, institutional leaders, and state/national policy makers. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]