While many have extolled the potential of Webbased instruction, rarely has this enthusiasm been backed by reliable evidence. Ruth Colvin Clark and Richard E. Mayer in £-Learning and the Science of Instruction (2003) elaborate pedagogical principles which should be followed to maximize the effectiveness of hypermedia and web-based instruction (terms they combine as e-leaming). They explicitly cite the research on which they base their claims as well as provide examples from training programs in current use to demonstrate how their principles might be applied. The result is a definitive handbook of guidelines for instructional designers that is based on the best-available academic research, written in an accessible language which minimizes the use of academic jargon.