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?

The newly reconstructed motet Beatius/Cum humanum is remarkable in several respects. It ranks among the longest of Ars Nova motets, and divides neatly into three parts of which the middle is an eighty-breve untexted hocket section. It also contains an extended quotation – textual as well as musical – from the Fauvel motet Firmissime/Adesto. The quoted material speaks of ‘Trinity and unity’, turning a spotlight onto the tripartite form of Beatius/Cum humanum. Firmissime/Adesto has occasioned comment because it is built up of duple (‘imperfect’) notes even though it praises the perfect Trinity. Beatius/Cum humanum can be read as participating in the same conversation. By shifting the salience of the number three from local rhythmical organisation to the global level of form, it serves as an example of how music can depict perfection ex imperfectis.

The copyist of the manuscript Oxford, Bodleian Library, Canon. Misc. 213 was detailed and well versed in numerous notational styles, and as a result, examples of unusual notation in this manuscript have drawn a critical eye. Yet the unique transcription of Binchois's rondeau Mon seul et souverain desir, in which the copyist alternates between the two common note shapes for the semiminim in the cantus voice, has thus far gone unexplained. This notation has no rhythmic significance; as such, it appears to be a superficial anomaly. In this article, I lay out a rationale for a reading of the notation of the semiminims in this piece as potentially deliberate and meaningful. Over the course of compiling the manuscript, the copyist increasingly aligned semiminim shape with prolation: the full-black shape is used exclusively in minor prolation, whereas the void flagged shape becomes more frequently restricted to major prolation. Since the rondeau is in minor prolation, I suggest that the copyist might have used the void flagged figure in order to suggest a momentary shift into major prolation. In so doing, the copyist might have left to us a witness of a performance practice in which the mensural and rhythmic possibilities inherent in the built-in tension between and were explored.

The Liturgical chant bibliography 24 retains the traditional format: (1) Editions and facsimile editions, (2) Books and reprints, (3) Congress reports, (4) Chant journals, (5) Colections of essays and dictionaries, (6) Articles in periodicals and Festschriften. Additions to the bibliographies of previous years (mostly reviews) are listed directly after this introduction. This year's bibliography opens with five Cantus planus databases and indexes, which were introduced in a detailed review published in the Journal of the American Musicological Society, 67 (2014), 267–85 (24001).