The records of the Apostolic Penitentiary, one of the paramount medieval forums of conscience, have been increasingly mined during the last fifteen years. This is a booming and blooming field of research producing much interesting work. During the last decade especially, many national or regional studies and source publications on the Penitentiary records have been published, many of which are listed in A sip from the ‘Well of grace’. Kirsi Salonen and Ludwig Schmugge, both having long research experience of the Penitentiary records, have written an introduction to the late medieval sources produced by the Penitentiary. The result is a clear, concise and lucid – occasionally even humourous – book. Nevertheless, its structure invokes some comments. One would have expected the institution of the Penitentiary to have been presented first. Now, a novice to the subject may emerge confused, ignoring what the Penitentiary really was, what it did and why. It would have seemed logical to present its records and their survival only after such an introduction. Yet, it was enjoyable to read a short overview of the papal archives and the calamities that befell them. This explains the lacunae in the sources particularly before 1448. Reading about the presentation of the ‘production line’ of the documents and the administrative procedure of the Penitentiary was absorbing. Knowing how and through which stages the letters were produced is important when assessing the value of the sources and the facts of the cases. These stages are also well-illustrated by the selected texts. Yet, it would have been interesting to know why these particular documents were chosen. While the German/Swedish bias of the texts is obviously partly due to the fields of expertise of the two authors, one notes that examples from the British Isles and the Iberian peninsula are lacking. Some words of explanation of the criteria of choice could have been useful. The book is accompanied by a CD-ROM with digital photos of the selected texts. The images are clear, but do not seem to permit extensive magnification, perhaps requiring a higher resolution. It would have been intriguing to read some concise analysis of the national and regional patterns in the Penitentiary sources. There are some fascinating remarks here and there on the topic, for example of French religious individualism (pp. 67–8) to whet one's appetite. Indeed, such experts on the source material could perhaps have dedicated some pages to an overview and an analysis of the main differences between regional supplication patterns and the reasons behind them on the basis of present knowledge. Salonen and Schmugge offer some tantalising glimpses in their book, but further research would be welcome here. This could have been included in the conclusion to the book, had there been one. All in all, however, as an introduction to the office of the Apostolic Penitentiary, its records and the sources it produced in the late Middle Ages, this book admirably serves its purpose.