There have been a great number of books written about the critical Battle of Gettysburg, but few of them convey the drama and emotion experienced firsthand by Tillie Pierce (a 15-year-old school girl) and Dan Skelly (an 18-year-old store clerk.) Their stories are among the best civilian observations of the war. Matilda "Tillie" Pierce Alleman self-published "At Gettysburg: What a Girl Saw and Heard of the Battle" (1888), and Daniel Skelly wrote "A...