This encyclopedia is a living volume that provides an entry point for learning about the educational technology field and that evolves over time with additional contributions and resources. Representing the perspectives of educational technology researchers, instructors, designers, developers, and practitioners throughout the world, it includes short, focused articles on foundational topics ranging from learning and design concepts to emerging technologies to policies shaping the future of educational technology. Each article is peer-reviewed and intended to provide an expert and up-to-date understanding of the topic, while also providing a space for community contributors to share helpful resources related to the topic.