“I dedicate this work to Vasily Arkhipov, the deputy commander of a Soviet nuclear submarine off the Cuban shore who said no to his comrades and may have saved the world. That was on October 27, 1962, around the time my father came home from his defense job and told me at the doorstep to our house that there was “only a twenty-percent chance, son” the next day would never come. No terrorist action today remotely poses that kind of existential threat for our world, and I hope you’ll keep that in mind in reading on.”