The purpose of this book is to introduce you to 10 principles we have evolved for making every meeting matter. They reflect a good bit of refining that we have done on our methods. More to the point, they reflect persistent work on us. Despite recurrent bouts of self-doubt, we have let go of many theories and techniques we once relied on. How, for example, would you diagnose ''group needs'' when every person needs something different? We could no longer work successfully with increasingly diverse groups in a world of nonstop change using methods favoring homogeneity in more stable times. In this regard, too, we depart from mainstream meeting guides. To deal with diversity and uncertainty, we offer a single theory that you can use whether looking at organizations, groups, or yourself. It is a theory that we have tested in many cultures. We describe it in the introduction. If you hate theory, skip that part. Stay aware, though, that we ground our practical tips and techniques in research and theory going back decades. In bringing each principle to life, we have chosen to limit ourselves to a few practices that you can use all the time. We run meetings the same way with teens and senior citizens, students and teachers, artists and engineers, tribal chiefs and captains of industry, making only small adjustments that help people preserve norms central to their identity. We have learned to help people cooperate regardless of their differences by discovering capabilities they did not know they had.