As part of the Göttingen-based research project "Kleinüberlieferung mehrstimmiger Musik vor 1550 in deutschem Sprachraum" (Minor Transmission of Polyphonic Music Before 1550 in German-Speaking Areas), the Professor Emeritus for Historical Musicology, Martin Staehelin, has systematically indexed previously unknown late medieval sources from Germany and Switzerland. His extensive analysis of various works, including those from the collections of Basel monasteries, the Kassel University Library and the Herzog August Library in Wolfenbüttel, is prefaced by a chapter that presents the technical terms, research criteria and academic relevance of the theme.