Two models of literacy stand in contrast to one another. The first, termed the "autonomous model" by British anthropologist Brian Street, portrays literacy as a value-free, technical skill which effects uniformly positive changes in both individuals and societies. The "ideological model," in contrast, focuses on specific social practices of reading and writing, exploring ways that these practices are embedded in and shaped by different sociocultural contexts. It also examines the relationships between literacy practices and social stratification and control. The ideological model can serve as a theoretical framework for examining the variety of literacy practices which returning adult students bring to college basic writing courses. Two case studies from a basic writing course at a college in New York City illustrate a key distinction between nonschool literacies that can be considered public and those that can be considered private. The literacy that a Black woman had acquired in her work as a preacher, religious educator, and pastoral counselor was very much a public literacy and lent itself to adaptation for academic literacy tasks. The literacy that a Puerto Rican woman had acquired as a homemaker and letter writer was a private literacy in conflict with the norms and practices of academic literacy, and she was forced to struggle against rather than build on the literacy she brought with her to the basic writing classroom. The ideological model challenges basic writing teachers to examine and understand students' various nonschool literacies. (SR)