The bindings of a large number of manuscripts formerly held in the library of the Benedictine monastery of St Michelsberg in Bamberg preserve fragments of medieval chantbooks documenting a culture in which practical singing and music theory were closely intertwined. These remnants, the work of generations of scribes, reveal a sustained concern for correctness ranging from the use of pitch-clarifying neume notations, to the use of letters, to the recording of melodies along lines prescribed in theoretical works. The influence the music theorist Hermann of Reichenau on St Michelsberg's own theorist, Frutolf, raises two questions. First, what is the nature of the relationship between practical chant and music theory books at St Michelsberg? Second, how was Hermann's notation used at the monastery?