This collection of wide-ranging and stimulating essays is, as the editors tell us, a ‘festschrift for a book’ (p. 2), namely, Gerhart Ladner's The idea of reform (1959). Its aim is to ‘explore and critique the enduring significance of Ladner's study and to survey new avenues and insights of contemporary reform scholarship’ (p. 1). Reassessing reform consists of two parts. In part i, three of Ladner's former students critically assess their mentor's influence on their own work and on the larger field of patristic and medieval reform studies. Like their teacher, these scholars emphasise issues of methodology, philology and terminology. All three underscore the complexity and variety of the vocabulary of ‘reform’ (renewal, renovation, conversion etc.) and the complexity and variety of reform concepts or ideologies that this vocabulary reflects. Part ii presents a series of case studies and critical appraisals of Ladner's work. Chronologically, the case studies range from Gregory vii to the Protestant Reformation, but the emphasis is on the fifteenth century. In keeping with Ladner's taxonomy, these studies treat various types of reform, from personal to ecclesial to social; and several essays, such as William P. Hyland's article on the Premonstratensians and Dennis Martin's on the Carthusians, emphasise the interrelatedness of these various types of reform. Particularly notable among the contributions for its contrarian argument is Michael Vargas's ‘nominalist’ rejection of Ladner's ‘metahistorical constant’ of reform. Vargas insists rather on specific, contextualised instances of reform and on ‘an absence of absolutes for either reform's victory or defeat’ (p. 102). Also noteworthy is the connection (with its Augustinian overtones) between reform and memory that figures prominently in the essays by Ann W. Astell and David Albertson. Not surprisingly, the degree of indebtedness to Ladner's important book varies amongst the contributors, but this well-edited volume is marked by the uniformly high quality of all the contributions. It is a fitting tribute to the influential book that it celebrates. While Reassessing reform has no bibliography (a select bibliography of seminal works in ‘reform studies’ might have been desirable), the footnotes offer a wealth of bibliographical suggestions for further study.