A reconnaissance man and sniper, John Lewis Barkley served in Company K of the 4th Infantry Regiment, a unit that participated in almost every major American battle. The York-like episode that earned Barkley his Congressional Medal of Honor occurred on October 7, 1918, when he climbed into an abandoned French tank and singlehandedly held off an advancing German force, killing hundreds of enemy soldiers. But Barkley's memoir abounds with other memorable...