It is possible that e-textbook readers and tablet PC's will become mainstream reading devices in the future. However, knowledge about instructional design in this field of learning sciences is inadequate. This study aimed to analyse how two factors, that is, presentation methods and concept maps, interact with cognitive load and learning outcomes when the contents of e-textbooks are compiled. Further, it endeavored to suggest an adequate logic of instructional design based on the findings. An empirical method was adopted, and 78 participants--either undergraduates or graduates in college--were recruited. Regarding the compilation of e-textbooks, the findings can be summarised as follows: (a) Providing concept maps not only reduces learners' cognitive load but also enhances their learning outcomes of cognition, affection, and psychomotor performance. (b) Overall, video (V) is superior to text and diagram interaction (TDI) in terms of learning outcomes, and TDI is superior to text and diagram (T&D). Nevertheless, within the cognitive domain, learning outcomes produced by V are not necessarily superior to those produced by TDI. When learners are not provided with concept maps, TDI is superior to V in terms of learning outcomes. Conversely, if learners are provided with concept maps, V is superior to TDI.