Good books draw in readers in their opening pages. I hope Forbidden Fruit does the same.In those pages I justify my choice of title. I also explain the need for counterfactuals and offer examples of just how committed policymakers, historians and international relations scholars are to the inevitability of important events. They are so to the point of obvious absurdity. And they also believe, against all evidence, that big events must have big causes.Readers must wonder why otherwise intelligent people do this and why all of us want to see the world as explicable and partly predictable. A bit unsettled, intellectually and emotionally, the reader, I hope, will be interested in learning more about the way the world actually works and why we hold to and defend simplistic and often logically contradictory understandings about our world.The significance of this book is two fold.The first is methodological, a word and concept that might seem far-removed from real-world concerns. But methods guide our thinking and can lead us into counterproductive, even disastrous, political, economic and social policies. By developing the counterfactual method, I aspire to improve policy analysis.More importantly, counterfactuals provide alternate worlds from which we can observe our own from distance and think with more detachment about it and about us. This is essential to probe not only how our world works but who we are and how we have become ourselves.