The presence of turbulence in multiple areas of our society-food, fuel, and finances-being but three critical areas presently being impacted means that long-held assumptions are no longer true, that the past is not prologue, and that the future is not clear. And enter into this unstable present the discipline of evaluation-a discipline formed and shaped in the past fifty years of stability, little turbulence, and strong assumptions that everything will go according to plan. If things do not go well, it is because of either a poor theory of change on how to bring about positive outcomes, or weak efforts at implementation. It is not because of the stormy present upsetting our quiet past. As it is, conventional evaluation behaviour and beliefs are ill suited for these times. The transformational nature of the 'Arab Spring' is just one arena in which it is clear that a business as usual approach to evaluation is entirely inappropriate. The papers in this volume are from the 2011 Global Assembly of the International Development Evaluation Association (IDEAS). Nearly 350 development evaluators from eighty-five countries came together in Amman, Jordan to discuss and analyse the consequences of turbulence on evaluation. The intent of these papers is to systematically assess what changes have come during this time of turbulence and how these changes are impacting the craft of development evaluation. To be clear: this book is not about how to assess the impacts of crises on development and on people's lives. It is about the meaning of a changed world and changed assumptions on the concepts and methods used in evaluation.