As a war correspondent, Wilbur Fisk was an amateur, yet his letters to the Montpelier Green Mountain Freeman comprise one of the finest collections of Civil War letters in existence. "Literary gems," historian Herman Hattaway calls them. "It would be believable that some expert novelist had created them." But Fisk was no novelist. He was a rural school teacher from Vermont, primarily self-educated, who enlisted in the Union Army simply because he...