The phenomenon of adult functional illiteracy in the United States is examined, and strategies are considered for addressing the problem. Reasons for the failure of existing programs (schools, adult education, and volunteer tutoring) to close the literacy gap are explored; among these factors are the relative growth of underserved populations, increased technological demands, and the small proportion of the target population that is currently receiving literacy training. It is argued that stimulation of informal literacy training and spontaneous acquisition of literacy skills form an important, but neglected strategy. One-to-one interactions to help someone accomplish a literacy task afford critical opportunities for informal literacy education. Next, a preliminary theoretical framework for adult literacy development, encompassing both formal training and spontaneous acquisition, is described. Implications of this model for reaching nonparticipants are explored through the concept of situation specificity; this section illustrates general and specific barriers to participation for different age groups, Hispanics, Blacks, and offenders and exoffenders. Finally, an outline of a research agenda suggests ways to enhance outreach efforts in adult literacy. A reference list concludes the document. (SK)