E Learning and the Science of Instruction by gurus Ruth Colvin Clark & Richard E Mayer (2011 edition) sub titled “Proven Guidelines for Consumers and Designers of Multimedia Learning”
A hugely popular and influential book, now in its third edition, and available on the Kindle….doesn’t get much better than that!
This work is solidly based on research, and that is why we like it so much, so if you are a serious about understanding what works in e-learning, this is the work for you. DP