This project explores the use of computer simulation for helping students of biology at all levels master an increasingly complex body of information. This simulation faithfully represents the state of biological knowledge, displays information in visual form, and is fully interactive and engaging to novice users. The simulation is of the human immune system. These simulations play a critical role in understanding the functioning of the immune system itself. The most valuable first use of the model will be to make difficult concepts in the immune system easier to understand. The simulation is the basis for a highly interactive, compelling educational game for teaching immunology at the high school and freshman college levels. The learning objectives and instructional strategies will be developed in consultation with biology teachers, at both the high school and college freshmen levels, and with learning research scientists. The project involves a multidisciplinary team with expertise in: (a) the complexities and subtleties of the underlying biology; (b) the information technology needed to build complex simulations and visualizations; (c) the instructional objectives and strategies best suited for the target audience; (d) application of the software tools to build games that people in the targeted age groups will find engaging and motivating; and (e) evaluating the impact of game/exploration-based instruction. This project will build on work on development of an instructional game for immunology supported by the National Institutes of Health and research on learning technologies supported by several public and private resources.