Throughout this book there has been an effort to provide an historical context for the various elements that contribute to the development and use of geothermal energy. Knowledge of the events that have contributed to the growth and success of geothermal use provides perspective on underlying issues that inuence whether an application or concept will succeed. For geothermal energy that historical context is brief, barely spanning 100 years. Even so, signicant advances in understanding and technological capability have motivated rapid growth, particularly in the last 50 years. And yet, as suggested by much of the material in this book, that growth may well be little more than the initial stage of geothermal energy applications playing a much larger role in the global energy landscape. This chapter considers some of the important new resources and technologies that are likely to inuence growth in the near future.