No Spot of Ground — Walter Jon Williams

After years of civil war, the genius of Edgar Allan Poe is nearing the breaking point. Poe has devoted himself to the Confederacy, but his dreams of honor and glory are drowned in blood and slaughter far more vast than the terrors of his imagination. Anguished, tortured by memories of his dead wife and his dead hopes, Poe finds himself holding a key position against Grant's assault, and must decide whether or not to sacrifice all that he still loves in service to a dying cause.