This dissertation is an effort to demonstrate the design engineering of three multimedia instructional programs. It presents the design studies of three multimedia applications that combine both the effect of multimedia and instructional strategies used in these applications. It contributes to a reasoned and researched set of principles that can be applied effectively using a variety of media in a variety of settings. The evaluation of these multimedia applications conducted in real classrooms allows the researcher to derive instructional principles that are both grounded in theory and supported by evidence from authentic tasks.