A wide-eyed teenager during most of the Revolutionary War, Joseph Plumb Martin left his grandfather's farm in Connecticut in 1775 and spent much of the next eight years with the Continental Army, crisscrossing the mid-Atlantic states and returning north after the British surrender at Yorktown. His notes, penned when he was seventy, recount in grim detail his harrowing experiences during the conflict -- the staggering losses in human life, the agony...