With few exceptions, the development of adult intelligence assessment instruments has proceeded along the lines of the Binet-Simon tests for children, stressing psychological assessment over the evaluation of what an individual knows. These tests, developed over 90 years ago, were quite effective in predicting school success, but were much less predictive of success in postacademic and occupational domains. Several lines of research have converged on a redefinition of adult intelligence that places a greater emphasis on content (knowledge) over process. The problems an adult is asked to solve almost always draw on accumulated knowledge and skills. For an adult, intellect is better conceptualized by the tasks a person can accomplish and the skills he or she has developed. Research has made it clear that current methods of assessing the intellectual performance of adults are inadequate. The challenge for researchers in the future will be to develop batteries of tests that can be used to assess different sources of intellectual knowledge for different individuals. (Contains 12 references.) (SLD)