This impressively learned book argues that Piers Plowman not only draws on but also contributes to late medieval debates among canon lawyers about topics related to contrition and penance. The premise comes from the company kept by some copies of Piers. In particular, the libraries of medieval clerics such as Walter de Brugge and John Wormyngton contained works on canon law as well as Piers Plowman. To further bolster this premise, Thomas also refers to the illustration in Oxford, Bodleian Library, MS Douce 104, depicting a “priestly figure that . . . is iconographically analagous to” an illustration in a “canonistic treatise on penance” (5), and to fragments of a canon law text found as flyleaves in Aberystwyth, National Library of Wales, MS 733B, a conjoined copy of the A and C texts of Piers.

While flyleaves can be astonishingly random, programs of illustration are not, and the evidence of wills is undeniable: Piers Plowman demonstrably moved in clerical, even canonist, circles, and it is well worth considering the implications of such readership. But this book is not a study of readers. Rather, it argues that canon law was not a fixed set of decrees but a process of interpretation, such that it has “common ground with fictional writings [such as Piers] that also interpret norms and thereby shape them, even if only at the level of concepts” (15). “The level of concepts” is a key phrase. Rather than focusing on verbal echoes, Thomas argues that Langland's characters rely on “a commonly available conceptual language” (99) that they use to analyze legal and theological questions.

The book is organized around the stages of penitence: contrition, confession, restitution, and satisfaction. Its admirably clear introduction presents the main themes, arguments, and texts to be considered, defines the book's relationship to the “law and literature movement” (10), and clarifies the types of evidence to be considered. Chapter 1 studies the confessions of Mede and Contricion, or rather, their performance of contrition, in passus B3 and C3, and B20 and C22. Chapter 2, focusing on usury in canon law and in the B and C versions of Piers, addresses ways of thinking about restitution, and argues that Conscience repurposes “the canonist logic of corporeal usury” to present a new view of “spiritual usury,” a concept canon lawyers treat skimpily (112–13). Chapter 3 continues to address restitution, via the confession of Covetise (B5 and C6); and Chapter 4 shifts to satisfaction, through the trial of Wrong (B4 and C4). Chapter 5 wraps up contrition, confession, and satisfaction through study of Patience's sermon (B14, C16). The epilogue returns briefly to material culture, quoting Luther's list of canon law volumes that he burned, including many studied in Thomas's book alongside Piers Plowman.

Since much of Thomas's argument relies on conceptual rather than lexical similarities, some readers might wonder if his claims are more a question of reader response than of authorial intent. That is, while a medieval canon lawyer might read Piers and see these points being worked out, one might nonetheless ask if that means that Langland was deeply familiar with the sources, or if he picked up on their ideas from friends and interlocutors. Ideas and problems surrounding confession, contrition, and penance were of interest to people other than canonists. Nonetheless, the book certainly elucidates the differences between B and C with respect to problems regarding charters, pardons, performance, and contrition, with church law proving a strong tool in this process. Throughout, Thomas provides strong organization and guidance to the reader through section divisions and signposting of his argument, as well as providing extensive examples to support his claims. Even where these may be arguable, the terms of the argument are well defined and easily taken up for further debate. Thomas engages with and builds on the work of many contemporary scholars, as well as making medieval canonistic texts available in extensive quotations and English translations. His familiarity with these sources is remarkable. This book is a substantial contribution to current scholarship. There is no comparable study. The scholarly community will appreciate the book's detail and analysis.