Could Lincoln have lived? After John Wilkes Booth fired a low-velocity .44 caliber bullet into the back of the president's skull, Lincoln did not perish immediately. Attending doctors cleaned and probed the wound, and actually improved his breathing for a time. Today medical trauma teams help similar victims survive-including Gabby Giffords, whose injury was strikingly like Lincoln's. In Diagnosing Giants, Dr. Philip A. Mackowiak examines the historical...