The Sixth Marine Division holds a unique place in U.S. Marine Corps history, because it was retired after one great battle. The division was formed on Guadalcanal in September 1944, its ranks filled with battle-hardened veterans and untested replacement troops. The Sixth Division fought its only action on the island of Okinawa from April to June 1945 but entered the fight with more combat experience overall than any other Marine division in its initial battle. It disappointed no one. The Okinawa campaign involved eight Army and Marine divisions, but the Sixth captured most of the ground in...