The design of effective instruction is centrally important for education and can benefit from the diverse expertise of all the contributors to this book (i.e., subject-matter experts, teachers and curriculum developers, educational researchers, and cognitive scientists). Because of a somewhat unusual career, I have had a "foot in all these camps"—as a research physicist, physics professor, textbook author, and researcher in education and cognitive processes. I may, therefore, be in a good position to provide a broadly-based perspective about some salient problems of instructional design.