Low literacy levels in adult learners pose an educational and public health challenge to practitioners and the scientific community. Increasing demands placed on literacy can limit opportunities in the workplace and access to health-related resources, negatively affecting public health. Current estimates from the National Center for Education Statistics suggest that more than 40 million adults in the United States possess only the most basic and concrete literacy skills. Despite the estimated number of learners possessing minimal literacy skills in English in the United States, there remains a paucity of research focused on adult learners to inform remediation efforts. This special issue of the "Journal of Learning Disabilities" represents an important step in highlighting the current scientific knowledge base and the implications for future directions and lines of inquiry with adult learners. (Contains 3 notes.)