Florence Chave-Mahir's monograph is the most substantial academic study of exorcism in the Middle Ages. Ordered chronologically, it traces the representation of demoniacs, demonic possession, the exorcist and exorcism, from their interrelated origins in the early Church, up to the fifteenth century. Different types of source are employed to cross-check the findings which are presented, so that the drama of exorcism and its protagonists are viewed through a prism of hagiographical, didactic and liturgical accounts, complemented by artistic depictions (where devils are small, dark beings, drawn from the mouths of the demoniacs). When it came to the matter of diagnosis, Chave-Mahir shows that the line between possession and mental illness was seldom clearly drawn, even though learned medical texts prescribed medicinal remedies for mental attacks that were commonly attributed to demons. In regard to the cure: that is, the exorcism, she emphasises the drama of that highly-charged, ritualised encounter, together with the spiritual power at the exorcist's command (at least, in the minds of the audience), as the essential ingredients. Saints of course, who were patterned on Christ, the first exorcist, were mighty in this good work. Several shifts of thinking emerged during these centuries. At the outset, exorcism was associated with the expulsion of devils from pagan neophytes at baptism. In the eleventh century, accusations of diabolic possession began to be levelled at deviants: at heretics (in the histories of Raoul Glaber) and at sodomites (in the letters of Peter Damien). During the thirteenth century, the association of heresy with diabolism was becoming commonplace and yielding to the assumption that heretics were consensual in allowing the devil to gain control over them. Possession was also feminised, as an evil mainly afflicting women. These twin developments foreshadowed later concerns about women who courted the devil – or witches, as they became. Although cases of possession were frequently reported, the exorcist, in that century, appeared less and less. In his place arose the confessor and the inquisitor as those at the forefront of the war against demons, while the devil also fled before a surge in eucharistic devotion. Manuals for exorcists, which began to multiply in the fifteenth century, suggest that much of the drama was over by that point; demonology had become more academic. Those familiar with the contours of socio-economic change over these centuries can set these developments in their broader context. Chave-Mahir is content to chart them with her focus rather narrowly on exorcism, so although her many materials are admirably introduced the wider currents of change are left for the reader to navigate. In this respect, the study shies away from total history and veers towards the learned, compendious assemblage. If there are omissions in such a comprehensive work, these relate to the war against demons on a grander scale, which later chapters touch upon but earlier ones eschew. If confessors and inquisitors formed its vanguard in the thirteenth century, who was at the forefront in the eleventh and twelfth centuries? (Anchorites, monks and missionaries might be the answer.) Some attention to revenants, notionally corpses possessed by devils, would have informed the discussion of how the diabolic invasion of bodies, dead or alive, occurred. Still, these are matters to be explored in future debate. Chave-Mahir's compendious book will satisfy much of our curiosity.