After his 2004 The German Fleet At War, 1939-1945, 2007 The U.S. Navy Against the Axis: Surface Combat, 1941-1945, and 2009 Struggle for the Middle Sea: The Great Navies at War in the Mediterranean Theater, 1940-1945, here's O'Hara's 2010 masterpiece: in a sense, if the three former told the "what", the latter explains the "why".
This time O'Hara is co-editor, primus inter pares with Dickson and Worth, of an unusual and extremely innovative book. The seven great navies of WWII are thoroughly described in separate chapters written by reputable experts adopting a fixed analytic framework. Moreover, every chapter is provided with a short order of battle and, a definite plus of the book, a map of bases and organization, whose graphical symbols lets immediately appreciate the importance and facilities of the bases of each power (one only regrets the lack of a general map for the bases of the British Empire).
The amount of information provided in the book is awesome: of the 38 pages devoted to the often neglected French Navy I particularly appreciated the section dealing with the evolution and evaluation of ships and weapons; the 41 pages concerning the German Kriegsmarine are delightfully crammed with numerical data; except for the section about command structure and personnel, the 43-page chapter by Wragg has little in common with (and is more interesting than) his previous Royal Navy Handbook 1939-1945 (Sutton, 2005), moreover he spends six pages describing the other Royal Navies (Canadian, Australian, New Zealand, Indian, and South African); the shortest chapter (34 pages) relates to the Italian Regia Marina and provides particularly new and surprising details about intelligence, surface warfare doctrine, gunnery, and final assessment; by contrast, the subsequent chapter is the most ample (52 pages) and extravagant, but the Imperial Japanese Navy, the only non Western navy, deserves the special treatment of a masterly written 11-page backstory and 4-page final reflections; not surprisingly, the American chapter is the second longest (44 pages) and matches the Japanese one, particularly when analysing the tactical doctrine devised to fight the expected annihilation battle with the Japanese fleet (noteworthy are the tabular "Standard Battle Plans" and the graphical "Armor Penetration Study"); the Soviet chapter (36 pages, the second shortest) sheds light on a somehow obscure matter, and lets the reader discover how much the Communist Navy owed to the Fascist naval technology (the Montecuccoli-like Gorkii cruisers, the Galileo-like fire-control computers, the Italian scartometers and torpedoes, the Balilla-like Series I U-Boats, the Isotta-Fraschini engines for the MTB, the Italian-made turbines, not to mention the Italian-built fast destroyer leader Tashkent etc.).
In such a specialized book for navy buffs, the 29 pictures (not particularly well reproduced) are unnecessary and I would have rather liked 29 additional tables or charts instead. Worth a mention is the bibliography, not only fairly ample (10 pages) but also commented, and the guns and torpedoes comparative tables in the appendix.
Quite paradoxically this remarkable five-star book has one big flaw: as a delicious pie is always too small or a dream holiday too brief, so this succulent work is too short. First, the extraordinary quantity of comprehensive information provided would have required a much deeper apparatus than the scant 78 endnotes (none of which, for instance, gives details about the surprising draw in the cryptologic war between the celebrated British code-brakers and their neglected Italian counterpart: 13.75% vs. 13.3%); anyway, expanded notes and errata can be found at the book's site. More important, the book lacks a sizable introductory (or final) chapter of the kind of that that Harrison put at the beginning of The Economics of World War II: Six Great Powers in International Comparison (Studies in Macroeconomic History) (Cambridge U.P., 1998), an international multi-authored work whose structure On Seas Contested recalls. Despite the fixed framework of the latter, the coordination among the chapters remains loose, so that we have rather parallel descriptions than actual comparison. For example, both the British and Italian chapters stress that the rate of fire of the Royal Navy artillery was frantic and particularly the double of that of the Italian Regia Marina (by the way, this explains much about the outcome of the duels between these two navies: ceteris paribus, the more shells you spend the more hits you get), it would have been therefore interesting to know if, say, the cold-blooded Germans used to fire like the phlegmatic and miserly Italians or if the wealthy Americans were as frenetic as their British allies. Another example: the British chapter affirms that trade convoys to and from the United Kingdom comprised 85,775 ships (plus another 175,608 in coastal convoys); the German chapter, on the other hand, says that Allied merchant ships made more than 300,000 successful Atlantic voyages and 100,000 more in British coastal waters; in neither case the sources are quoted and some explanation of these apparently so different statements would have been advisable.
Despite these minor imperfections (which hint how still unexplored the subject is), On Seas Contested is a monumental work, that every naval enthusiast should possess.