Book excerpt: Design for Learning in Virtual Worlds, the first book focused specifically on how to design virtual worlds for educational purposes, explores: • the history and evolution of virtual worlds • the theories behind the use of virtual worlds for learning • the design of curricula in virtual worlds • design guidelines for elements experienced in virtual worlds that support learning • design guidelines for learning quests and activities in virtual worlds. The authors also examine the theories and associated design principles used to create embedded assessments in virtual worlds. Finally, a framework and methodology is provided to assist professionals in evaluating "off-the-shelf" virtual worlds for use in educational and training settings. Design for Learning in Virtual Worlds will be invaluable both as a professional resource and as a textbook for courses within Educational Technology, Learning Sciences, and Library Media programs that focus on gaming or online learning environments.