According to conventional wisdom, the British navy entered the First World War obsessed with the threat posed by Germany's fleet of modern battleships. Naval leaders of this period, infused with the ideas of Alfred Thayer Mahan, were supposedly so preoccupied with the pursuit of a decisive battle with the German fleet that they failed to think seriously about the defense of Britain's seaborne trade against scattered German commerce raiders. The result, we are told, was the inconclusive Battle of Jutland in 1916 and the near victory of the German U-boats the following year. Revisionist historians have recently claimed that the Royal Navy did give serious thought to trade defense but that this was directed against a perceived threat from the armored cruisers of France and Russia. Both schools agree, however, that naval leaders were not particularly concerned before the war about a German challenge to British trade.

Matthew Seligmann's important new book takes on both interpretations. Traditional accounts of this period have dwelled, he notes, on the navy's prewar failure to predict the German U-boat threat and the service's seemingly irrational opposition to convoy during the first years of the war. Seligmann makes a strong case, based on exhaustive archival research, that the navy did not ignore the problem of trade defense. It was just looking in the wrong direction. The Admiralty may have dismissed the idea that the Germans would use submarines to attack British commerce, but for over a decade before the outbreak of war it was concerned with an entirely different threat to British shipping: German armed merchant cruisers. This has gone largely unnoticed, according to Seligmann, because the relevant documents are widely scattered in the surviving Admiralty records. By systematically pulling this material together, he is able to show that from 1902 onward, the Admiralty was alarmed by the possibility that Germany would arm its fast civilian liners in wartime to prey on British commerce.

Admiralty officials took this threat seriously right up to the outbreak of war, and most of the book is devoted to their efforts to develop countermeasures. Seligmann's mastery of the archives and judicious analysis are evident on every page. At first, naval leaders were drawn to the idea of arming Britain's own fast merchant ships. To this end, subsidies were provided to Cunard for the construction of two very fast liners (Lusitania and Mauritania) suitable for conversion to armed merchant cruisers in wartime. However, naval opinion gradually swung round to the idea of using warships to counter German armed merchant cruisers. In a chapter dedicated to the origins of HMS Invincible, Seligmann shows that Admiral Sir John Fisher and his supporters developed the new “battle cruiser” class of warship specifically with this threat in mind. This conclusion is directly at odds with the revisionist interpretation of the battle cruiser's origins popularized by Jon Sumida, but the evidence Seligmann deploys is formidable. Fisher himself was quick to revert to the idea that battle cruisers should be used to intercept fast (and potentially armed) German liners after the outbreak of war in 1914. The new warships' original purpose has been obscured, however, by Fisher's obsessive secrecy and by the desire of other admirals to use the heavily armed warships as part of the main battle fleet—a role in which they failed dramatically.

The Admiralty also lobbied for changes in international law that would prevent Germany from arming its merchant ships in wartime, although these efforts were unsuccessful. A different approach was adopted after Winston Churchill became First Lord of the Admiralty in 1911. Under his leadership, the Admiralty began preparing to arm British merchant ships for self-defense. This involved considerable effort, including complex negotiations with shipping companies, a careful examination of international law, and the training of a new class of naval reservists. In 1912, guns were mounted for the first time on a handful of suitable British merchant vessels. This was considerably cheaper than building large numbers of cruisers to deal with German commerce raiders, but Seligmann shows that Churchill was not interested in arming all of Britain's merchant ships. He hoped that a relatively small number of the new defensively armed merchant ships could be used to police the trade routes and offer a degree of extra protection to unarmed merchant vessels. As the problems with this policy became increasingly apparent, Churchill's enthusiasm for the scheme began to wane, and by 1913 the Admiralty was again considering the idea of commissioning fast British liners as auxiliary cruisers in wartime.

The history of the Royal Navy in the years 1900–14 has become a lively and controversial field in recent years, and this book is a noteworthy addition to the growing body of scholarship critical of the revisionist arguments advanced by scholars such as Jon Sumida and Nicholas Lambert. The volume undermines their influential account of the origins of the battle cruiser and challenges their claims about the centrality of France and Russia in the Admiralty's calculations. But on the whole, Seligmann treats the revisionists gently: he does not stop to consider how his findings will affect their conclusions about the broad direction of British naval policy during the Fisher era, even though the implications are considerable. What is most impressive, however, is that Seligmann is able to show with equal force that traditional histories of this period have also misunderstood key aspects of British naval policy. The book will be essential reading for anyone interested in the history of the Royal Navy in the Fisher era.