The history of naval warfare in World War I centers on the Battle of Jutland, the dramatic yet inconclusive encounter between the British Grand Fleet and the Kaiser's High Seas Fleet on 31 May 1916. But these expensive armadas spent most of the war resting at anchor while other ships conducted the real, day-by-day fighting in a trade war that featured the successful British blockade of German ports and German retaliation by unrestricted submarine attacks on British shipping.

Historian Matthew Seligmann traces the backgound of this commerce war, which unfolded in ways the Admiralty did not anticipate. The British Empire of 1890 depended upon its vast merchant fleet to supply its needs from colonies around the globe. These freighters in turn relied on the Royal Navy to guarantee their safe passage on the seas. But, as the turn of the century neared, the dominance of these two fleets was no longer unchallenged. British admirals, looking out across the North Sea, were disturbed by what they saw:

Seligmann devotes his slender book to the British response to this challenge. The Admiralty and the government as a whole considered, and at least partially adopted, several approaches: changing international law to ban any country from transforming merchant ships into armed cruisers while at sea; arming large, fast British liners; equipping ordinary merchant ships with defensive weapons; creating an intelligence network to track German ships; and building fast new warships that could chase down German auxiliary cruisers.

Seligmann chronicles how both German and British plans for the trade war evolved between about 1902 and the outbreak of war in August 1914. He uses not only the considerable secondary literature on the subject,[1] but, more significantly, German and British official documents. His painstaking archival work was complicated by the British government's weeding of its archives, especially those of the Admiralty, in the past sixty years, which left many of the relevant reports and files catalogued but missing. Fortunately, Seligmann's hard work paid off in some cases: for example, if Royal Navy copies of correspondence on arming merchant ships were lost, he might find them in the Cabinet Office papers or at the Treasury. Nonetheless, he has often had to make educated guesses about just what officials actually wrote. Despite this, he provides a detailed account of British and German prewar naval strategies.

British diplomats' efforts to ban the refitting of merchant ships as auxiliary cruisers were thwarted by stubborn German opposition at law-of-the-sea conferences. Although nothing much came of the British government's talks with Cunard and other shipping lines about modifying new liners—the Lusitania and Mauretania, for example—to carry guns, the program of Defensively Armed Merchant Ships (DAMS) did bear fruit: many such ships were later able to fight off attacks by German surface raiders or U-boats. Still more successful, Seligmann believes, was the Admiralty's creation of a global intelligence network, gathering reports by British officials stationed overseas and merchant captains arriving in ports around the world. This system served Britain well in both world wars.

Seligmann's discussion of the ultimate solution—building warships that were fast enough to overtake any German armed liner—is the best treatment of the origins of the battlecruiser I have seen. The introduction of steam turbines made it easy to construct large, swift warships that could run down the speedy liners despite their high freeboard and powerful engines. In the event, the new class of warships had a checkered history—three blew up at Jutland and, in 1941, the Bismarck sank the HMS Hood, the largest battlecruiser ever built. Admiral Sir John "Jacky" Fisher, the moving force behind the battlecruiser, never explained exactly what these novel ships[2] were intended to accomplish. If, as Seligmann believes, they were meant to destroy fast German auxiliary cruisers, why were they built with such heavy armament, when smaller guns would have sufficed? And why were they never deployed for that ostensible purpose once the fighting started?

Although the text proper of the book concludes with the outbreak of the First World War, an Epilogue and Conclusion furnish a succinct explanation of naval actions during the war. Germany did turn four liners into Hilfskreuzern, the fast auxiliary cruisers the Admiralty so feared. Seligmann duly notes that the German vessels sank only about 400,000 tons of shipping, not much compared to the damage inflicted by the later U-boat campaign. But the fates of the four ships were quite dramatic: two engaged in successful commerce warfare for months before interning themselves in neutral American ports in 1915. A third was sunk by a Royal Navy warship after a short battle. And, finally, the Cap Trafalgar fought a duel with a British armed liner, HMS Carmania, that left both vessels badly damaged and on fire. The British ship got credit for the victory in this unique action, when the Cap Trafalgar sank.[3] Seligmann then tells the story of the fast Cunard liners, which did not fight, and of the DAMS, which did—and effectively. He touches as well on the role of Royal Navy battlecruisers during the war.

A real strength of Seligmann's explanation of British naval policy in the decade leading up to the war is his close attention to the interplay between naval officers, prime ministers, and other government and corporate officials in Great Britain. German policy making is addressed as well, but more briefly, with stress on the British failure to understand German intentions when it came to arming liners. This book is not aimed at most naval history readers, but it will interest scholars who want to know more about how political and diplomatic history influence what appear to be military affairs.