Caught up in global chaos, the navies of World War II had to fight campaigns that rarely matched prewar planning. Each country found itself adapting its fleet compositions, ship designs, personnel training, and weaponry to ever-changing circumstances and ever-fluctuating resources-with varying degrees of success.

An understanding of the successes and failures requires an uncompromising critique of the tools of war. Fleets of World War II pins down the warships' actual qualities, a nation-by-nation survey covering everything from the mightiest battlewagons to modest patrol craft. After...