A Boston Globe Bestseller

On December 26, 1941, Secret Service agent Harry E. Neal stood on a platform at Washington's Union Station watching a train chug off into the dark and feeling at once relieved and inexorably anxious. These were dire times. With Hitler's armies plowing across Europe--seizing or destroying historic artifacts at will--and Japan's devastating attack on Pearl Harbor just three weeks prior, American officials now feared an enemy attack on Washington, D.C.

So, President Franklin D. Roosevelt set about hiding the country's valuables. On the train...