Among opportunities to advance the state of the art of intelligent computer-assisted instruction (ICAI) are the evaluation of ICAI systems and the use of the underlying technology in ICAI systems to develop tests. Each issue is addressed via its theoretical context, key constructs, appropriate references to the literature, methodological aspects, and concrete examples of the feasibility of resolving the issue. ICAI systems use artificial intelligence and cognitive science to reach a range of subject matters. Several computer programs are discussed. The key components of ICAI systems include a knowledge base, a student model, and instructional techniques for teaching declarative or procedural knowledge. Research that has contributed to the development of ICAI includes research into both formative and summative evaluation, measurement of student achievement outcomes, measurement of individual differences among students, and process measurement and analysis. A list of 75 references is presented. (TJH)