Keegan (The Mask of Command, 1987); Six Armies in Normandy, 1982; The Face of Battle, 1976; etc.) here offers a bravura appreciation of naval power down through the ages. In aid of his era-spanning study, the former Sandhurst lecturer (who points out that no Briton lives more than 80 miles from tidal waters) examines four landmark naval engagements, each of which featured different types of warship. First off, he analyzes 1805's battle of Trafalgar, in which England's wooden-wall vessels under the command of Lord Horatio Nelson defeated a French/Spanish fleet in atypically decisive fashion. More than a century later, in 1916, Germany's dreadnoughts achieved a Pyrrhic sort of victory over the Royal Navy off Jutland--the first clash of ironclads. With his customary economy and flair for telling detail, the author also recounts the battle of Midway, where US carrier forces slugged it out with a similar Japanese flotilla to gain an upper hand in WW II's Pacific theater. Last but not least, he audits the long-running Atlantic campaign in which Nazi U-boats (at no small cost) took a terrible toll on Allied shipping. Although Keegan focuses on just four remarkable conflicts, he does not restrict himself to their immediate circumstances and implications. In an interpretive afterword, for instance, he comments on the significance of UK losses to missiles and aircraft during 1982 encounters with Argentine forces around the Falkland Islands. The author does so, moreover, in the context of the development of true submarines (as opposed to "merely submersible" ships). Conceding that underwater communications remain a problem, Keegan speculates that one day the world's oceans may be largely empty of surface vessels. In addition, he assesses the piratical origins of naval warfare and includes a wealth of nautical lore. During the Napoleonic Wars, for example, British sailors threw dead comrades overboard (to keep decks clear for fighting); their French and Spanish foes had to do battle amidst the fallen because Catholic widows could not remarry in the absence of bodies to bury. A hell-and-high-water chronicle that's as absorbing as it is illuminating. The concise text includes 16 pages of black-and-white illustrations (not seen).