In this study, the authors compared four multimedia learning arrangements differing in instructional approach on effectiveness and efficiency for learning: (a) hypermedia learning, (b) observational learning, (c) self-explanation-based learning, and (d) inquiry learning. The approaches all advocate learners' active attitude toward the learning material but show differences in the specific learning processes they intend to foster. Learning results were measured on different types of knowledge: conceptual, intuitive, procedural, and situational. The outcomes show that the two approaches asking learners to generate (parts of) the subject matter (either by self-explanations or by conducting experiments) led to better performance on all types of knowledge. However, results also show that emphasis on generating subject matter by the learner resulted in less efficient learning. (Contains 12 tables and 2 figures.)