Investigators have moved back and forth between design efforts and basic studies in cognition to improve both application and fundamental knowledge. This volume's theme is this interaction between practice and science with the opportunity for reflecting on findings in order to understand them and suggesting improved forms of application and their underlying explanation. This is seen in various arenas including theory-based computer-assisted instruction for teaching mathematics, the design of communities of learning in elementary schools, teaching in the context of problem-solving situations and reasoning with models, self-explanation as a highly effective learning activity, conceptual change in medical training and health education, and workplace training in electronic troubleshooting. The results of extensive long-term experience and analysis in each of these areas are insightfully reported by the well-known contributors to this volume. Special features of this fifth edition include: * The work of eminent cognitive scientists in the design and evaluation of educational and training environments to increase current understanding of learning and development, as this understanding is applied to innovative instructional programs and teaching methods. * A description of learning theory and principles as well as implications and examples on research and development on educational application. * A presentation on the 10-year change in perspective on research and development in problem solving environments that invite inquiry about academic information and skills in the context of instruction of elementary school children. * An innovative approach to math and science instruction in which teaching is oriented around constructing, evaluating, and revising models. * An examination of the process of self-explaining, which involves explaining to one's self in an attempt to make sense of a new situation. * A description of a long-term program of cognitive task analysis and instructional design on problem solving in the operation of complex equipment. * An investigation on the acquisition of clinical reasoning skills and the understanding of biomedical concepts in both professional medicine and the health practices of the lay population.