Beginning at Chattanooga, Catton chronicles Grant's successful battle to save a beleaguered federal army there and his selection as head of all of the armies of the Union.
The strategic plan, the overland campaign, the investiture of Petersburg and the finale with Lee at Appomattox are chronicled well.
What Catton does very well here is focus on Grant the General-in-Chief. We see how Lincoln and Grant are drawn toward each other through a shared and fundamental understanding of what it would take to win the war and the will to do it -- incredibly a trait Lincoln could find in no other General selected to head the Army of the Potomac.
The actual management of the Union's armies and efforts is given great attention. Even the Civil War devotee who knows a lot about the battles of the war will appreciate this focus on grand strategy, army management and the particular and singular attributes possessed by Grant to manage the affair to a successful conclusion.
A wonderful book, as is it's predecessor, "Grant Moves South."