We have fed our sea for a thousand years
And she calls us, still unfed,
Though there's never a wave of all her waves
But marks our English dead:
We have strawed our best to the weed's unrest,
To the shark and the sheering gull.
If blood be the price of admiralty,
Lord God, we ha' paid in full!"
-- Rudyard Kipling, "Song of the Dead"
If blood indeed is the price of admiralty, then all sides paid full measure during the Second World War. Both the European and Pacific theaters included major battles and even whole campaigns at sea. As I got interested in WW2 primarily through naval warfare, this is what I have the most books about. They can be grouped into half a dozen major categories:
Note: This page contains books about surface ships and battles. Books that focus on naval aviation can be found here. Books about submarine warfare are here.