Of all the threats faced by the Royal Navy during the first years of the twentieth century, the one which stood out was the risk to Britain's sea lines of communication posed by France's armored cruisers. Fast, well-armed, and well-protected, these ships could have evaded any attempted blockade of the French ports and, supported by a worldwide network of overseas bases, could potentially have caused havoc on the trade routes. The primary focus of the book is on the technical characteristics of the ships. Detailed and labeled drawings based on the official plans are provided by John Jordan, and each individual class of ship is illustrated by photographs from the extensive personal collection of Philippe Caresse. The technical section is followed by a history in two parts, covering the Great War (1914-18) and the postwar years, during which the surviving ships saw extensive deployment as "station" cruisers overseas and as training ships. This is the most comprehensive account published in English or in French and is destined to be the standard reference for many years to come.