Richard E. Mayer, Ph.D., is a Distinguished Professor of Psychological and Brain Sciences at the University of California, Santa Barbara. His research focuses on the intersection of cognition, instruction, and technology. He is the author of more than 600 publications, including 40 books, and has been recognized as the most productive educational psychologist in the world. Ruth Colvin Clark, Ed.D., is the President and Principal Consultant of Clark Training & Consulting. She is a specialist in evidence-based training methods and bridging the gap between academic research and practitioner application.