Parsi has written a detailed and gripping account of the 22 months of negotiations over Iran’s nuclear program that resulted in the 2015 deal struck by the Islamic Republic and the permanent members of the UN Security Council plus Germany (known as the P5+1). Iran pledged to eliminate its stockpiles of uranium, drastically limit its enrichment activities, and allow inspections of its nuclear facilities. In exchange, the P5+1 agreed to lift crippling sanctions on Iran. Parsi did not participate in the negotiations but has interviewed just about everyone who did. His book captures the ebb and flow of the process—indeed, its psychology. The United States saw sanctions as a way to force Iran to negotiate; Iran saw enrichment as a way to force the United States to negotiate. Neither wanted to put down its stick. There is no doubt in Parsi’s mind that the only alternative to the deal was war, which was U.S. President Barack Obama’s position, as well. Further sanctions would not have produced regime change in Tehran, Parsi contends. He also does not believe that Iran—a big, diverse, proud nation—could be isolated indefinitely. The Trump administration may think otherwise, but Parsi presents a convincing argument that normalization with Iran, although not inevitable, is possible.