A furious, all-or-nothing German winter counterattack caught the Allies by surprise. Their lines shattered, American soldiers fought with guns and guts and bayonets to slow down the onslaught; fought to separate their comrades from Germans dressed in U.S. uniforms; fought to survive the horrors of such battle sites as Baraque de Fraiture, Elsenborn Ridge, or the infamous Malmedy massacre of unarmed POWs. When it was over, the Allies had suffered 81,000...