This paper reports the existence of an unpublished monograph by Friedrich Gisinger (1888-1964), entitled Die periegetische Form in der Antike and written in the 1950s. This work was found as part of the scholar’s Nachlass in the Bayerische Staatsbibliothek (Munich); its interest lies in the peculiar interpretation of ancient geography it offers. Because of his innovative views on this matter, Gisinger, who was collaborating to the FGrHist project, argued with Felix Jacoby and Herbert Bloch.