Max Boot, an independent researcher and journalist, is well-known as the author of The Savage Wars of Peace.[1] In the present, ambitious volume, he surveys guerrilla warfare from the beginnings of civilization to the War on Terror. By means of a long list of test cases, he discriminates the various types of guerrilla war, stressing the antiquity of this style of fighting. Although the term entered the military lexicon only in the course of the Napoleonic Peninsular War (1807–14), "guerrilla" warfare in fact predates conventional war. Walter Laqueur has noted that the Hittite king Morsilis I (c. 1556–1526 BCE) complained that irregular forces did not dare attack him in the light of day, preferring to assault his forces at night. Archaeological and anthropological evidence attests that guerrilla fighting preceded both written history and "ordered" war-making.[2]

Nonetheless, most histories emphasize regular wars rather than small, hard-to-document, unconventional, inglorious military clashes (simmering colonial and civil wars, tribal conflicts, and partisan activities). And, too, it is challenging to classify all the forms of irregular fighting in disparate regions and historical periods. Still, consistent patterns of action are discernible. The Gauls fought Julius Caesar with methods like those the Spanish used against Napoleon over eighteen centuries later; Scottish guerrillas at the end of the thirteenth century used tactics like those of the Mujahidin during the Soviet occupation of Afghanistan in the 1980s.

There is about guerrilla war something commonsensical, almost instinctive, that does not fit the theoretical writings of students of regular warfare, with their stress on professionalism and strict hierarchical authority. The Gallic leader Vercingetorix summed up its rationale when he asserted that, to beat the Romans, the Gauls must deprive them of provisions and shelter by striking their supply caravans (impedimenta) and isolated units, or even by adopting scorched-earth tactics.[3] Two thousand years later, Mao Zedong endorsed the same tactics against the regular Japanese army.

Though widespread, guerrilla warfare rarely led to decisive military victory before 1945, except in conjunction with regular armies. Thus, for many years, despite dogged guerrilla resistance, neither the French nor the British withdrew from their imperial holdings. But, some argue, guerrilla fighters at times contributed to political successes. For example, the guerrilla war in the southern colonies during the American Revolution enabled George Washington to rehabilitate his army and cooperate with the French at the battle of Yorktown in 1781. And Cuban guerrillas brought about American intervention during the Spanish-American War in 1898. Guerrilla war has continued to figure prominently in military struggles where one side lacks conventional forces.

Irregular warfare tends to occur in three situations. First, when insurgents turn to it after their regular army has been beaten; the classic example is Spain during the Peninsular War. Second, when there is no regular army to begin with, as was the case for Native Americans in the Old West. Third, when irregular forces assist regular armies; an apt example is T.E. Lawrence's organization of Bedouin tribes to assist the British in World War I. Because they operate in small units, we can add special operations forces to the latter category. In all cases, we have to do with, in Boot's phrase, "invisible armies."

For several reasons, Boot concentrates on the period since about 1950. The first is the paucity of sources for guerrilla war from the ancient and medieval eras. For instance, there is little information beyond their mere identification for the roughly 120 irregular wars he isolates in the first two centuries of the Roman Imperial period; indeed, the actual number of such conflicts is likely much larger.

Secondly, before the twentieth century, guerrilla war—despite its prevalence—only slightly affected the balance of political and geopolitical forces and thus drew far less attention from historians than major wars fought by regular armed forces. This is especially striking in the hundred years from the end of the Napoleonic wars (1815) to the outbreak of World War I (1914), when Britain fought only one regular war (the Crimean War of 1853–56), but its armies were preoccupied with colonial wars in India and Africa. So too, France and the United States in the same period engaged in several regular wars, but were similarly entangled in protracted wars against irregular forces: the French in North Africa and Southeast Asia, the Americans in their western territories and, at the close of the century, in the Philippines.

A final reason for Boot's modern focus is that guerrilla war was transformed in the second half of the twentieth century. From a mere tactical tool wielded in the shade of regular forces, it emerged as a means of effecting major geopolitical change.

Though, as in other general histories of guerrilla war,[4] the overall scheme of Invisible Armies is chronological, individual chapters or groups of chapters address specific defining characteristics of various kinds of irregular war.

In the first of the volume's eight "Books" (scil., Parts), "Barbarians at the Gate: The Origins of Guerrilla Warfare," Boot discusses guerrilla war from the third millennium BCE through the Middle Ages. Book 2, "Liberty or Death: The Rise of Liberal Revolutionaries," describes guerrilla wars and counter-wars from the mid-seventeenth century to the 1870s, principally in Spain during the Peninsular War, Greece during its war of independence, and Italy in the Risorgimento. Book 3, "The Spreading Oil Spot: The Wars of Empire," deals with colonial wars conducted by European countries, especially in the nineteenth and early twentieth centuries. In Book 4, "The Bomb Throwers: The First Age of International Terrorism," Boot begins with a definition of "terror" as a distinct phenomenon, differing from guerrilla war, which "must be carried out by a substate group" (205) against military forces, though civilians often suffer. He admits this is a problematic definition (xxi–xxiv). He includes here a fascinating chapter on a radical religious split within the Isma'il Islamic movement in Persia and Syria. This splinter group, the Assassins, was the first to mount suicide attacks in the name of Islam. Another chapter in Book 4 treats the Ku Klux Klan in America's south after the Civil War. Such movements were chiefly urban, not rural in nature. Boot sees in this roots of the transition to urban guerrilla warfare generally identified with the 1960s and 1970s.

Book 5 investigates "The Sideshows: Guerrillas and Commanders in the World Wars." Highlighted are the exploits of Lawrence of Arabia, Charles Orde Wingate (the "friend" in the collective memory of the State of Israel), and Josip Broz Tito, as well as the development of special operations forces in World War II. Helpful here would have been a chapter dispelling the mythology surrounding the activities of guerrilla and underground movements that operated during the Second World War: they were not decisive in bringing victory over the Axis powers; moreover, in many places, they were most conspicuous after the war in their efforts to overturn political opponents that had secured their countries' independence. In Vietnam, the Philippines, Malaya, Yugoslavia, and elsewhere, guerrillas did in fact operate against Japanese or German occupiers. But, however much of the burden of war fell on their shoulders, they received critically important external aid from the United States and Great Britain. In the end, Germany and Japan were beaten, in the air, at sea, and on land by the huge American and Soviet militaries.

The process of decolonization is discussed at length in Books 6, "The End of Empire: The Wars of 'National Liberation,'" and 7, "Radical Chic: The Romance of Leftist Revolutionaries." The withdrawal of European, particularly French and British, occupation forces spawned bloody guerrilla wars that continued to the mid-1970s. Because most guerrilla organizations espoused clearly communist principles, their struggles figured in the ideological confrontations of the Cold War. In a series of test cases—China, Malaya, the Philippines, Algeria, Vietnam, and others—Boot analyzes changes in the nature of guerrilla war initiated or inspired by Mao Zedong, whereby it acquired a strategic role in generating revolutionary political change. Mao was not a tactical innovator. The unique element of his thinking was an emphasis on the people's struggle. That is, he saw guerrilla warfare as the means to attain strategic and, most importantly, political goals. Book 7 also contains chapters on the Cuban revolution, the attempts of Che Guevara to export communist revolution to Africa and Latin America, and the actions of Yasser Arafat and the PLO. Book 8, "God's Killers: The Rise of Radical Islam," covers Islamic terrorism from the Iranian revolution to America's wars in Iraq and Afghanistan.

Boot is careful throughout to integrate some scrutiny of the response of various regular armies to the guerrilla phenomenon. He is also concerned to place irregular war in the broader framework of military history (557–58). Unfortunately, he accepts at face value certain entrenched myths. For example, he states that Great Britain lost much of its empire to the actions of irregular forces, as during the American Revolution and, two centuries later, in its fight against Zionist militias (557). But the Revolutionary War ended with a decisive conventional battle between the British army and Washington's Continental army acting in concert with French forces. As for Palestine, neither Israeli irregulars nor Arab fighters were as decisive a factor as the British Empire's dire economic situation after World War II. Indeed, several months before it transferred the Palestine question to the United Nations (November 1947), Britain had awarded independence to India, once the jewel in its imperial crown. Where the British did choose to persist in their fight against irregular forces—Malaya and Kenya—it managed to defeat them in a variety ways.

We should bear in mind that Mao, the father of modern guerrilla warfare, repeated again and again in his writings that only a regular army could overcome an enemy's regular army. Mao had a decisive influence on the military thinking of the Vietnamese commander, Vo Nguyen Giap, who claimed[5] that guerrilla forces had beaten the French at Dien Bien Phu—another myth. History shows that, in 1954, the elite French troops faced the regular army that Giap had built with Chinese assistance, an army rationally structured in brigades and divisions, with artillery, light tanks, antiaircraft cannons, and a sophisticated logistics system. Furthermore, its victory at Dien Bien Phu did not alter the strategic realities in Vietnam, as France continued to rule the large cities and population centers in the Mekong and the Red River deltas.

The withdrawal of conventional military forces in the face of guerrilla aggression has most often been the consequence of political factors, not military setbacks. Irregular forces played only a subsidiary role in forcing the pullout of the French from Algeria, the Americans from Vietnam, the Soviets from Afghanistan, and the Israel Defense Force from Lebanon in 2000. (Indeed, Israel has stood strong against irregular fighters throughout its sixty-five-year history.)

Boot ends with a short section entitled "Implications: Twelve Articles, or the Lessons of Five Thousand Years," reiterating that the guerrilla phenomenon, in all its various manifestations and principles, has been universal in time and space. In his well written narrative, he makes good use of archival research and firsthand sources and shows himself fully conversant with the abundant secondary literature. Invisible Armies is a valuable contribution to the study of guerrilla warfare in history and it will provide a sound starting point for future interpretations, whether corroborative or dissenting.