Hermann Potzlinger (+ 1469), the university-educated schoolmaster of the monastery of St Emmeram, Regensburg, was the creator of one of the largest and most intriguing collections of late-medieval polyphonic music to have survived from Central Europe. His music book, the so-called "St Emmeram Codex" (Munich, Bayerische Staatsbibliothek, Clm 14274), was compiled in the years immediately following his graduation from Vienna University in 1439. It contains a unique cross-section of polyphonic vocal music not only from the West but also from Central and Eastern Europe; moreover, it is only one among more than a hundred scholarly manuscripts that he copied or acquired during his career. This volume presents an in-depth study of the manuscript and of the professional networks and academic culture within which it was compiled; its context as part of one of the largest surviving personal libraries of its time is also explored.