Maybe Doomsday preppers aren’t so crazy after all. As nuclear threats loom from countries like Iran and North Korea, the US is knocking the dust off decades-old bunkers intended to protect government officials — and even start a new civilization — in the case of just such a nightmare event. Journalist Garrett Graff takes readers through the 60-year history of the government’s secret Doomsday plans to survive nuclear war in his painstakingly researched book “Raven Rock: The Story of the U.S. Government’s Secret Plan to Save Itself — While the Rest of Us Die” (Simon & Schuster), out now. He...