The April 1945 journey of FDR's funeral train became a thousand-mile odyssey, fraught with heartbreak and scandal. As it passed through the night, few of the grieving onlookers gave thought to what might be happening behind the Pullman shades, where women whispered and men tossed back highballs. Inside was a Soviet spy, a newly widowed Eleanor Roosevelt, who had just discovered that her husband's mistress was in the room with him when he died, all...