The earlier editions of this classic on so-called low-intensity conflict appeared around the turn of the century. Their author was a British soldier-scholar with considerable personal experience and a wide-ranging intellect. In the introduction, Douglas Porch, perhaps the leading American historian of France's military, makes the case for the book's enduring relevance as a study of how the weak may often thwart the strong in this peculiar kind of warfare. Callwell understood well that irregular warfare posed a problem different in kind, and not merely magnitude, from that of conventional warfare. As a result, his thoughtful examination of the perennial frustrations of colonial powers in dealing with their amorphous opponents is illuminating. While his tactical injunctions about the uses of the infantry square or the advantages of camel corps are not terribly relevant to contemporary tacticians, his depiction of the general problem remains worth perusal.