"War is not an aberration" (xii), asserts noted historian Margaret MacMillan (emerita, Univ. of Oxford), with no beating around the bush. Her sweeping new survey ranges from prehistoric violence to the future of warfare, driving home a simple truth: we cannot hope to understand what it means to be human unless we seek to understand military conflict.

Violence, the author reminds us, was deeply rooted in the behavioral propensities of our primate and Paleolithic ancestors. The more we learn about our species' distant past, the more the mirage of Rousseau's peaceful, primordial Golden Age has given way to Hobbes' vision of life as nasty, brutish, and short; the Leviathan of the state has played a key role in both pacifying societies and condoning belligerence. As sociologist Charles Tilly so memorably puts it, "War made the state and vice versa."[1]

As MacMillan observes, "war is perhaps the most organized of all human activities" (xxi), especially in the pre-modern age, when most human endeavors were more localized than they are now. Only warfare and religion transcended the small world of households, clans, and villages. War-driven state formation shored up central governments and laid the foundations for modern finance. Elites conducted war to enrich themselves, but it could also undermine entrenched inequalities and privileges. And, too, across the ages, technological progress has been tied up with military conflict.

The author singles out the modern industrialized version of war as a specially potent agent of change. It has welded local communities into nations, and national populations into armies of millions. Economic capacity became crucial to success as civilians became inescapably immersed in the business of war: the expanding franchise and new media drew in the masses as food rationing and bombing redefined their daily lives.

MacMillan shows that reasons for war have never been lacking. She detects already in Homer's epics such motives as honor, fear, and greed as well as religious and ideological commitments. Leaders make false claims that wars can solve any number of problems. But, once underway, they can acquire a momentum beyond the control or even imagination of their instigators.

The author discusses why (mostly) men[2] fight even at the peril of premature death. Combat has often been seen as a test of manhood in which officers imposed discipline, constant drill instilled muscle memory, and comrades inspired valor. In societies where military service was for the few, soldiers gained prestige by standing out. When conscription was the norm, soldiers strove to fit in as neatly as possible. Both incentives helped keep the machinery of war from sputtering.

Technology has enabled war as well. Metal weaponry, horses, and gunpowder were the chief innovations until the Industrial Revolution dramatically expanded the scale and scope of war. Various developments altered the experience of battle, as MacMillan argues in a fine chapter well suited to her anecdotal narrative style. Her stories of ground combat vividly convey the endemic confusion and overpowering sensory stimuli of battle. In a perverse dialectic, war strengthened the bonds of comrades in arms even as it violated all notions of order and morality, empowering soldiers to curse, destroy, rape, maim, and kill.

MacMillan opens her discussion of the role of civilians in war with stories of sexual violence perpetrated by the victorious Red Army in 1945. Long before the days of total war, civilians suffered as cities were sacked and residents displaced. Modern mechanized warfare spread such miseries more widely, both in fact and in the public imagination. For the first time, news media and the advent of cheap cameras brought war into every home. Mobilized civilians on the home front faced trials that rivaled those endured by combat soldiers. The two World Wars inflicted privations that removed distinctions between front and hinterland, man and woman. Many of the latter found a means of liberation, however temporary, by participating in the economic war effort.

MacMillan portrays war as an untamable beast. Only near the end of her book does she offer a glimmer of hope when she turns to efforts to control the seemingly uncontrollable. The nineteenth century witnessed incipient multilateral efforts to regulate the practice of war. Yet conventions have proven easier to sign than to enforce. Early twentieth-century hopes that economic globalization could prevent Great Power conflicts are a cautionary tale in the twenty-first. Democratic peace theory—i.e., that democracies are less likely to go to war against each other—awaits a world where functioning democracy is universal. MacMillan displays a healthy skepticism about such constraints, but one wishes she had considered the potential irenic effect of graying populations.

The book's final chapter concerns the place of war in the popular imagination and public memory. MacMillan touches on poetry, music, painting, and film, among much else. But is it really true that "certain wars stimulate more and better art than others" (239) or necessary to reject the strawman idea that "great art grows only out of the horror and futility of war" (240)? She is on firmer ground in characterizing memories of war as perpetually unstable and liable to be recast in the light of later events. World War I, once considered a necessary sacrifice, is now an exemplar of foolish waste.

The author makes a whirlwind tour across millennia of bloodshed around the globe, though mostly in its western hemisphere. A steady stream of anecdotes certainly enlivens her narrative but proves that less is sometimes more. Tasty morsels appear so swiftly as to obscure her overarching thesis. This is especially true of her treatment of the pre-modern world. She is more lucid and compelling in mapping the dynamics of warfare in the last two centuries of Western history, her natural scholarly habitat. When she credits military competition with innovations such as medical triage, jet engines, and computers, she ignores the likelihood that war merely accelerated developments that would have occurred in any case, if more slowly.

MacMillan's eclectic overview will engage and instruct a popular audience. Her narrative style well captures the frantic staccato of war, the hail of arrows or machine-gun rounds. Even as we duck for cover, we are reminded of those who could only grit their teeth and brave the onslaught. Though specialists seeking original insights and analyses may want to turn elsewhere, MacMillan has addressed an important paradox. While there is robust (and lucrative) demand for war-themed books, movies, and computer games, the appeal of actual military service has waned, and "in the majority of Western universities the study of war is largely ignored" (15). Have our attitudes become more one-sided? Is it a matter of distance—physical and intellectual—at a time when our news media report only the carnage and not the valor? MacMillan's keen observation about academic fashion points to another puzzle: in contexts where the faintest triggering can be held to cause significant psychic pain, war must seem the ultimate evil, a terrifying monstrosity best kept at arm's length. As a consequence, war, which one way or another has shaped everything around us, no longer shapes our thinking.

MacMillan ponders whether the reflex of recoiling from war may be confined to the West and other rich and stable societies. She raises the specter of renewed violent conflict driven by populism and climate change. Her concerns are fully justified. We cannot afford simply to "let all memories of war slip away" and "avert our eyes from something we may find abhorrent" (272)

I would go further. This is not just a matter of whether we remember war but precisely how we remember it. Margaret MacMillan's captivating account taps a rich tradition of scholarship on the perplexing and contradictory consequences of war through history. Organized fighting has yielded both good and bad. We must find it in ourselves to take in the full picture in all its facets.