Literature on cognition and learning in young adults is surveyed. First, an outline of a theory of the cognition-learning system is presented, reviewing the characteristics of each of the major components of the system. Particular attention is paid to the differences between young adults and other age groups in information processing skills. Literature on cognitive abilities and achievements of young adults is then reviewed. The main focus is on changes in achievement and ability organization in the high school and post-high school years. (Author/GK)