Unprepared for invasion, Tennessee joined the Confederacy in June 1861. The state's long border and three major rivers with northern access made defense difficult. Cutting through critical manufacturing centers, the Cumberland River led directly to the capital city of Nashville. To thwart Federal attack, engineers hastily constructed river batteries as part of the defenses that would come to be known as Fort Donelson, downstream near the town of Dover. Ulysses S. Grant began moving up the rivers in early 1862. In last-minute desperation, two companies of volunteer infantry and a company of light artillerymen were deployed to the hastily constructed batteries. On February 14, they slugged it out with four City-class ironclads and two timber-clads, driving off the gunboats with heavy casualties, while only losing one man. This book details the construction, armament, and battle for the Fort Donelson river batteries.