Medieval canon law is a source genre extremely rich in social, political and economical information. It is, however, relatively difficult to access due to the fact that very many of the collections of canon law are either not printed at all or available only in notoriously unreliable prints such as Migne's Patrologia Latina series. Fowler-Magerl's book, especially with the included database on CD-ROM, makes this farrago of texts more accessible to those who are not specialists in this rather arcane field. Once the reader has learnt how to use the database--a "Help" function is unfortunately lacking and the documentation on pp. 242-270 is not overly complete--he has at his disposal a reliable guide to more than 100 early medieval collections (most of them unprinted) from the 6th through mid-12th century with more than 100,000 legal texts.
The database includes a number of fields, among them the name of the collection, the location of the text within the collection (in the vast majority of cases for unprinted collections even the exact location in the manuscript the author has used), the rubric, the inscription as well as incipit and explicit of the text. Thus, it is possible to find out for most collections at least the major interest the author has followed in his work and what kind of material he has used and, not least, to see how a specific text travelled through history. This painstaking work is the major achievement of more than thirty years of labour. This book and the included CD is the third and so far most complete version of this database (earlier versions appeared in 1998 and 2003). The database appears very reliable (and reasonably fast) and certainly is of invaluable help for anyone working with early medieval canon law texts.
The small companion volume contains brief (and in many cases very helpful) characterizations of the collections analyzed for the database. Unfortunately, the printed characterizations are not always as reliable as the database itself, e.g. the "occasion" for the Pittaciolus of Hincmar von Laon was certainly not "the trial of bishop Rothad von Soissons" (64) but the Hincmar's own quarrel with his namesake-uncle, the archbishop of Rheims. The collection attributed to Remedius of Chur is not derived from two different sources (Pseudo-Isidore and an excerpt from the register of pope Gregory I, cf. 61) but only from one single source (a manuscript which contained both). The Hispana Gallica Augustodunensis was not just "used" by the Pseudoisidorian forgers (40) but fabricated by them. But it would be unfair to criticize Fowler-Magerl for such minor mistakes, perhaps unavoidable in a book which spans a half-millennium of sources very unevenly analyzed by past scholars.
The user of the database would probably have a few desiderata: Fowler-Magerl's book is not likely to be replaced any time soon. A CD-ROM is expected to have a lifespan of max. 50 years- -sometimes much less as many have no doubt experienced. It would be an excellent idea if the Monumenta Germaniae Historica could put online a version of the database. Furthermore, the programming language of the database (JAVA) is certainly today's standard for such exercises. It will not be forever. If past experience with programming languages is anything to go by, JAVA-programs might not even be understood by computers or operating systems in a few decades time. A very basic version of the database in ASCII and comma separated form (CSV) could make sure that even at some time in the future when MAC-OS X, Windows and Linux (the database runs on all these systems) will only be legends from a distant past, Fowler-Magerl's work will still be helpful to scholars.