What is required for effective teaching depends on the goal of the effort, and our criteria for success should be much more demanding than positive ratings from participants. If the goal is to improve participants' effectiveness as negotiators, we need a proven theory and associated skills. In the absence of robust confirming empirical data, which is still mostly lacking, we can take some confidence from qualitative evaluations. But whether or not we have a proven theory, the pedagogical task is complex and challenging, calling for a variety of sophisticated techniques deployed by a skilled instructor committed to joint learning. This article tells the story of some of the instructors' pedagogical learnings in thirty years of teaching the pioneering Negotiation Workshop at Harvard Law School, many of which now have empirical support. It also suggests some areas and tools for more experimentation in future advanced courses.