People have recognized the captivating power of music ever since it has existed. Its potential to affect the mind, the emotions, and the body is the source of myths from all over the world and across centuries. Music can heal but also be dangerous, and—to quote the title of a monograph by James Kennaway—be the “cause of disease” (Bad Vibrations: The History of the Idea of Music as a Cause of Disease [2012]). This striking ambiguity is at the core of Laurence Wuidar's book. By focusing on the role of music in the context of exorcism, the author tackles a fascinating subject that has thus far not received much attention in musicological studies. In order to do so, she scrutinizes a vast number of sources, ranging from manuals for casting out devils that discuss ways to recognize and cure possessed people, to instructions for inquisitors and judges, to treatises on music (such as Tinctoris's Complexus Effectuum Musices and Berardi's Miscellanea Musicale). Wuidar shows that music can be both a sign of possession by demons and a remedy against it; together with a plethora of other methods, such as prayers and medicine, music can help to restore the harmony of body and soul.

The main emphasis of the book is the period from the late fifteenth century, marked by the influential Malleus Maleficarum of 1486, to the eighteenth century, when manuals on exorcism start to decline and the rites are either put on the index, because of their proximity to magical practices, or are caricaturized. It is with good reason that Wuidar starts her investigation with a survey of biblical, patristic, and medieval literature, as there is a clear continuity in the field of demonology from pagan and early Christian writings to the Renaissance. The story of David playing the harp for Saul, who was terrified by an evil spirit (1 Samuel 16), is quoted throughout the centuries as powerful evidence of music's tempering role, with David—as precursor of Christ—reestablishing the harmony between heaven and earth.

It is the task of the exorcist to determine the physical and mental symptoms of the possessed and to assist them in expelling the demon from their body. To this end, all the senses were mobilized. As Wuidar shows in chapter 3, “Les apparitions diaboliques sonores et musicales,” the voice was both an important indicator and tool. A great number of manuals on exorcism stress the beneficial effect of the singing of psalms. However, this could also be abused by a demon, for the sounds he produces can cover a wide spectrum, from howls and terrible screams to sacred words and songs (the latter in order to seduce the victim). The possessed person in turn is often not able to sing or has become deaf or impervious to the Gospels or the ringing of bells, as Candido Brognolo observed in his Manuale Exorcistarum ac Parochorum of 1651. The evaluation of secular and instrumental music with regard to the healing process is generally much less consistent, not least because it is heavily dependent on the circumstances and the time period in question.

Wuidar also includes a chapter on such diverse phenomena as illicit exorcism, alternative forms of exorcism (such as the “thérapie musico-astrale” [236] proposed in Agrippa's De Occulta Philosophia), and parodies of exorcist practices (such as Bodin's De Magorum Daemonomania). The final chapter is devoted to witchcraft, especially to the place of music and dance in the pact with the devil and on a sabbat. This book will not only be of interest to musicologists. It talks about the role and power of music against the background of religious, magical, medical, and social practices, and it deserves to be read by historians of ideas, medical historians, theologians, and scholars working on the history of the senses. Given the complexity of the book's subject, it is regrettable that the index is limited to names only. It could have benefited from a more organized and differentiated system that also includes key concepts and cross-references, thus helping the reader to navigate through its contents more easily.