In our knowledge-oriented society, the necessity for novelteaching and learning paradigms has been leading to trends likedistance learning or e-learning. But very soon problems emerged inconnection with such technology-driven educational approaches.Adaptive e-learning tackles these problems through implementingdidactical competencies within information technology in order toimprove learning. This book examines aspects of adaptive e-learningand evaluates a technological prototype driven by two ideas:enhanced learner observation based on eye-tracking technology andretrieval-based instruction for adapting the learning process. Assuch, adaptive e-learning is being approached from differentangles, ranging from theory to practical implementation issues,accentuated with different concepts and evaluated through casestudies.