The Elucidarius magice (or Lucidarium artis nigromantice) is one of the texts of the end of the Middle Ages completing the legend of Peter of Abano as a magician. Preserved in two manuscripts of the XVIth century, printed several times under the name of Heptameron, this small textbook of nigromancy, condemned by abbot Trithemius at the dawn of Modern Times, proposes a rite of conjuration of the «angels» (in reality devils) attached to the subdivisions of time, to the planets and to the lower heavens, based on a compilation of various texts of medieval magic. The first aim of this paper is to review the evolutions of the text (from the manuscript to the printed matter), before bringing to a successful conclusion for the in-depth study of its sources, made possible by the recent advances of the research: among its founding texts appears the experimentum n° 37 of MS Munich, B.S.B., Clm 849, edited by Richard Kieckhefer, as well as the very demonic Clavicula Salomonis. But other sources are also mobilized. Lastly, the study of the sources of ritual magic allows us to identify better the connections that some of them were able to maintain at an earlier stage.