A history of the Royal Navy. Not bad. The impact of the force draw down after the end of the Napoleonic Wars was pretty interesting - I'd never heard that before but it's really not surprising: you really don't need dozens of Ships Of The Line once old Boney was shipped off to St. Helena. Also, a good discussion of the difference between H.M.S. Warrior (the world's second ironclad) and the U.S.S. Monitor (the third or fourth).
The part I thought was most interesting was the lost of individual Captain's initiative between Trafalgar and Jutland. The only explanation that makes sense is that this instinct was suppressed during the long period of peace. There's a lesson for us there.