In this chapter, we discuss research on learning from simulations and microworlds. After providing working definitions and examples for these environments, we review research on their effectiveness and, where available, on specific questions of their information design, interaction design, and instructional guidance design. On the basis of the research findings, we propose extensions to current theories of multimedia learning to involve social and affective processes and outcomes, describe implications for instructional design, discuss limitations of the existing research, and outline areas for future research.