Tracing the progress of the Pacific Theater of World War II, this book concentrates on the strategy and tactics used by each side. It details the U.S. plans and preparations for Operation Downfall, a planned invasion of Japan that the authors believe would have been far costlier in human lives than the D-Day landings in France. The authors reveal that both the Japanese and the Americans considered using poison gas, and that both sides had been assembling troops and ships in unprecedented numbers prior to the dropping of the bombs. Throughout the book, they maintain that the use of the bombs to end the war was both necessary and moral and saved many more lives than it took. To support this opinion, they discuss the personal beliefs of important decision makers including Truman, MacArthur, Marshall, and LeMay, and draw on documents declassified in the 1990s.