This book, which examines three key debates on medieval baptism, is a fine and fascinating achievement. Demonstrating an impressive dexterity with patristic and medieval sources between the third and fourteenth centuries, Marcia L. Colish delivers on her promise to illustrate church history ‘as it actually occurred’ (p.2). In tackling coalescing arguments over this period – with all their complexities, contradictions, inconsistencies and distinctions – she reveals a rich, diverse and discordant portrait of baptism and its place in the history of Christian thought. Beginning with the age of the Church Fathers, such as Tertullian, Cyprian, Ambrose, Gregory Nazianzus, Jerome, and especially Augustine, the contemporary discourse and doctrine on ‘baptism by desire’ (chapter i) is shown to have an enormous reception history well into the fourteenth century. It is precisely this legacy's re-emergence in the scholastic period of the twelfth and thirteenth centuries, Colish argues, that illustrates many patristic contradictions and key interpretive distinctions, the likes of which can be seen in the later works of Anselm of Laon, Peter Abelard, Bernard of Clairvaux, Roland of Bologna, Hugh of St Victor, Peter Lombard, Allan of Lille, Albert the Great and Thomas Aquinas (among others). Drawing on numerous historical contexts and literary genres, Colish next addresses a significant gap in the literature by representing some of the ‘concerns and conceptual tools’ (p. 92) applied by patristic and medieval thinkers to the subject of ‘fictive baptism’ (chapter ii). Her contribution to the scholarly discourse becomes even more apparent on the question of ‘forced baptism’ (chapter iii), which reveals just how few historians have treated its emerging theory and practice in any comprehensive manner. Here, Colish goes well beyond the familiar treatment of Jews to consider the later and unwilling conversions of indigenous pagans from the Carolingian era, as witnessed especially through the eyes of legal commentators like Ivo of Chartres and Gratian, and scholastic theologians like Lombard, Bonaventure, Aquinas, John Duns Scotus, William of Ockham and Durandus of St Pourçain. Through such careful and considered analysis, the intellectual origins of baptism become traceable in the dominant discourse of the High and Late Middle Ages. Overall, the traditions and conventions of baptism are richly contextualised in Colish's study, giving rise to nuanced considerations of intention and performance that populated medieval debates. Pastoral, polemical, political, legal, theological and psychological agendas informed all participants. Employing a variety of theological and canonical texts across the medieval centuries ensures that this book is not simply about the catechetical treatment of baptismal theology. Rather, its pages are filled with deep insights into medieval European society and psyche, captured at (and capturing) particular moments when baptismal arguments were invoked. Through Colish's impressive study, we learn a great deal about what and who mattered in these medieval debates, and why.