Recently brought to light by Johan Gumbert, “bat-books” are a codicological type of folded manuscript mainly used, in the 14th and 15th centuries, for calendars and almanacs. The BnF is preserving three such artefacts, one of them very peculiar. Latin 7478, a late continental almanac dated 1456, is derived from John of Gmunden Kalendarium, a very popular work rarely found in bat-books. Adapting and combining it with other vade mecum material, its copist, signing Friar Paulus de Kignin (or Szignin), otherwise unknown and probably not the only mind at work, is actively creating a new object. While using a very up-to-date Alfonsine material, however, this object doesn’t seem to be intended as an astronomical or medical companion, like we assume of many other bat-book almanacs, but most probably an innovative toolbox for mendicant preachers. Does the preservation of this sole uncommon bat-book mean that this attempt proved a failure ? Be that as it may, it seems to demonstrates a real try at appropriating astronomical Alfonsine data in the 15th century “civil society”.