The purpose of this book is to document sample lessons based on our What Works in Distance Learning: Guidelines (O'Neil, 2005). The intent is to provide an instantiation of our various distance learning guidelines. An overarching goal of our research was to create a robust and clear set of design guidelines and example lessons to support the next generation of distance learning systems. Each lesson in this book constitutes a case (Mayer, 2005) or partially worked example (Kalyuga, Chandler, Touvinen, & Sweller, 2001). A case is a description of a realistic problem scenario that is relevant to a particular profession or field of study (e.g., a case may be a distance learning lesson showing various instructors trying to design a lesson on a particular topic). A common topic could be, for example, how car brakes work, a surgery procedure, or electronics troubleshooting procedures (Mayer, 2003, 2005). In this book, the case format was useful for the guidelines developed for multimedia...