This text was written for a range of e-learning consumers and designers, from the novice to the seasoned. Drawing on a cognitive theory of how people learn and on scientifically valid research studies, the authors explain effective approaches to e-learning, including the best ways to use text, graphics, and audio; use of practice exercises and examples; what a learning agent is and how to use it in e-learning; and the use of collaborative Internet facilities. Clark has 20- plus years of experience in effective training for classroom or computer delivery; Mayer (psychology, U. of California, Santa Barbara) is an internationally-recognized expert in the application of learning psychology to instruction design in multimedia learning environments.