North Korea remains a puzzle to Americans. How did this country—one of the most isolated in the world and in the policy cross hairs of every U.S. administration during the past 30 years—progress from zero nuclear weapons in 2001 to a threatening arsenal of perhaps 50 such weapons in 2021? Hinge Points brings readers literally inside the North Korean nuclear program, joining Siegfried Hecker to see what he saw and hear what he heard in his visits to North Korea from 2004 to 2010. Hecker goes beyond the technical details—described in plain English from his on-the-ground experience at the North's nuclear center at Yongbyon—to put the nuclear program exactly where it belongs, in the context of decades of fateful foreign policy decisions in Pyongyang and Washington. Describing these decisions as "hinge points," he traces the consequences of opportunities missed by both sides. The result has been that successive U.S. administrations have been unable to prevent the North, with the weakest of hands, from becoming one of only three countries in the world that might target the United States with nuclear weapons. Hecker's unique ability to marry the technical with the diplomatic is well informed by his interactions with North Korean and U.S. officials over many years, while his years of working with Russian, Chinese, Indian, and Pakistani nuclear officials have given him an unmatched breadth of experience from which to view and interpret the thinking and perspective of the North Koreans.