What makes e-learning successful? In the development of quality in e-learning, it is now undisputed that learners, along with their preferences and requirements, must be given a prominent position. This volume presents, for the first time, an empirical model of individual learner preferences. It demonstrates which factors are significant for learners in e-learning. The foundation for this is data from qualitative interviews and the largest online survey on the topic to date, in which over 2,000 learners were asked about their preferences, competencies, and attitudes towards learning systems.