The DEAF is the key to French medieval literature, fulfilling a number of functions. The first is to provide bibliographical data for all the sources cited in the DEAF. The second is to give a substantive and qualitative characterisation of these sources, particularly of the primary sources. The third is to furnish the users of both the dictionary and the bibliography with further-reaching information, viz. the identification of the manuscripts, the dating and localisation of the texts and manuscripts, cross-references to the most important bibliographical handbooks and the abbreviations in neighbouring dictionaries. In addition, there is the central task of critiquing the literature cited? which allows the users to share in the editors’ wealth of experience. The new edition has been completely revised, with the amount of information three times that of the 1993 edition. The DEAF Bibliography with its system of sigla has become the benchmark for French historical lexicography.