It should be said from the outset that no review could do justice to this highly conceptual, thought-provoking and ambitious book that seeks to explain violence in the West in the past two millennia. Buc's claim is that violence is not ‘infinitely variable’ (p. 7): it assumes its shape based on the religious convictions of its actors which, for those areas in the West, are Christian. So Buc sets out to trace patterns in Christian and post-Christian violence to delineate the forms that they take, and to draw out continuities and commonalities across time. To accomplish this, Buc uses specific episodes across western history comparatively: the Jewish War; late antique martyrdom, Constantine's conversion, and the crusading era; the early modern Wars of Religion; the French Revolution; and late modern European left-wing militants, represented by Germany’s Rote Armee Fraktion. While Buc strays to extend specific points that he is making, these ‘nodes’ serve to ground the arguments in specific historical epochs while demonstrating their longevity, either through direct influence or later appropriation. The result is a thematic study that analyses a set of paradoxical dualities and how they influence western violence: the Old and New Testaments, peace and the sword, election and universalism, coercion and liberty.

It should be said that those looking for overarching lessons or ethical judgements will not find them here. Buc dismisses the latter as irrelevant, and although references are made to jihadis and Islamic fundamentalism here and there, the author maintains his focus on the Christian and post-Christian West. His ‘postface’ claims that holy war, terrorism and martyrdom will occur in the future, which will inherit the cultural forms of warfare of our own post-Christian age.

An introduction delimits and explains the book's aims, and also offers potted histories of the specific historical epochs that Buc references throughout the book. Chapter i illustrates the ways in which America's wars are emblematic of violence in the West, couched in terms of morality, self-purification, particular and universal liberty and religious freedom. Chapter ii explains the Christian dialectic between war and peace, showing that these binary notions, like orthodoxy and heresy, are interdependent. Buc uncovers how Christian attempts to resolve the tension between a bellicose Old Testament and a pacifist New Testament resulted in biblical interpretations infused with military images, the idea of ‘spiritual’ warfare, the oxymoron that peace comes about through violence, and apocalypticism. Chapter iii analyses the propensity to label terrorists as insane, identifying the origin of this tendency in Greco-Roman Stoicism, and tracing it in the polemics of early Christian persecution. Buc documents the belief that there could be ‘good’ and ‘bad’ possession throughout the pre-modern period until its subversion in the Enlightenment, and discusses the treatment of collective fanaticism in the modern era, especially in the emerging fields of social science. Chapter iv demonstrates that martyrdom is deeply connected to historical time. Because Christians believed that events in time were propelled by God's vengeance (including retribution for the killing of his martyrs), early Christians understood martyrdom to propel history forward. Buc also reveals the permanence of martyrdom's purging impulse (either purging the wicked from the elect or a purge among the elect themselves). Chapter v examines the link between national holy war and sectarian terror, arguing that when medieval princes devolved their power to coerce to lesser groups or individuals, this ‘elect’ was chosen for the defence and regeneration of the kingdom and the Church. Early modern ‘elect vanguard[s]’ (p. 208) assumed the duty to defend the religious common good; thus, popular violence for justice could be seen as legitimate. Chapter vi unpacks the close connection between liberty and coercion. Buc chronicles pre-modern debates about the use of force in matters of faith, pinpointing Augustine's acceptance of coercion for the sake of truth as authoritative. While the desirability of religious coercion waned in the Enlightenment, it emerged again among modern ‘political religions’. Chapter vii dispels scholars’ views that pre-moderns could not conceive of themselves as historical agents; Buc demonstrates that in fact medievals did conceive of human agency, which was necessary at times when God's cause was at stake. Christians came to see these historical events as partial fulfilment toward the End Times, and Buc posits that this notion of ‘violence as a motor’ for historical movement emerges again in the French Revolution and in modernity.

There are hallmarks of cross-disciplinary thinking throughout, including sociological and philosophical analytical frameworks, but this is a historian's book. Painstaking attention has been paid to historical agency, contingency, philosophies of history and an astonishing range of primary sources and their modern investigators. Although historical processes lie at the book's heart, Buc is not beholden to chronological continuity. The work jumps from one historical era to another and his arguments concerning the durability of ideologies are the more convincing for it.

That said, some might feel that that Buc's emphasis on continuities (or recurrence – he is careful to note that forms can ‘jump’ across time periods) elides important discontinuities. This approach undoubtedly makes a book on this scale possible, but it does leave this reader with lingering doubts about the nature of these recurrences. For instance, the political centralisation of the early modern era arguably shaped the phenomenon of heresy executions in the sixteenth century, as William Monter has suggested, but Buc has reduced the phenomenon of state building, happening ‘anytime’, to just one of several ‘outside processes’ (p. 68) that scholars have blamed for corrupting Christianity's peaceful origins. This is one instance of several in which one might wish to unpick the threads that Buc has artfully drawn together, but any reservations concerning certain continuities or recurrences, should not take away from the important and insightful analysis of the ways in which Christian theology has shaped Western violence. This enlightening book is original, sweeping in scope yet nuanced and careful in its evidence and explanations, and should certainly be read by scholars and graduate students with an interest in theology, history and forms of violence in the West.