This monograph focuses on some of the more complex theoretical issues that have plagued our discipline over time. Mengozzi's primary contention — stated on the dust-cover — is that modern scholars have misinterpreted an aspect of a method of sight-singing using six syllables (ut, re, mi, fa, sol, la, in modern parlance, “do re mi”), known as hexachordal solmization. This was the method introduced by the eleventh-century Benedictine monk Guido d'Arezzo as a teaching aid for enabling young choristers to learn new songs. While even musicologists familiar with the subject may find the history of musical theories in the first part of the text a challenge, the undaunted reader will find rewards in the later chapters. Here, Mengozzi links the reforms or ‘distortions’ of the Guidonian system made by fifteenth-century theorists to the intellectual, religious, political, and social trends of the Renaissance. The Guidonian method was intended, according to Mengozzi, purely as a practical pedagogical tool, not as the diatonic foundation of early music, as it later came to be regarded.

An introduction lays the groundwork for his thesis. The monograph is then divided into roughly two equal parts, part 1, “Guidonian Solmization in Music Theory and Practice” and part 2, “Reforming the Music Curriculum in the Age of Humanism.” Chapter 1, “Guido's musical syllables, a general review of the existing literature on the subject of hexachordal theory” reads like a who's who of musicologists from the late-nineteenth century to the present. Mengozzi critiques a number of noted contemporary scholars, among them Margaret Bent, Richard Crocker, Eric Chafe, Christian Berger, Karol Berger, and Dolores Pesce. Symptomatic of the controversy are the array of interesting monikers standing in for the six notes, including “floating pitches,” and the notion of the “hexachord as yardstick,” or as a “space-defining” and “position-finding” tool.

In Chapter 3 Mengozzi examines the theoretical writings up to the thirteenth century demonstrating that solmization theory had no more than a marginal presence. Although Guido's name was later associated with the ubiquitous mnemonic image of an inscribed hand, as an aid to modulation from one hexachord to another by using the joints of the hand to represent different pitches, the hand is neither seen nor mentioned in any of Guido's extant writings. Later in the chapter (Table 3.8), Mengozzi surveys the presence of “Guidonian” hands in sources to 1500. Although he cites Christopher Page's observation that there existed a “parallel between the ‘Guidonization’ of musical practice and the gradual embracing of Christianity in the religious and political institutions of Northern and Eastern Europe” (44), he fails to note important trends that took place following the advent of printing and the Reformation. Music texts in use at Catholic institutions contained images of the hand, while texts written for Protestants or by humanists substituted schematic diagrams of the hexachords or the scale. Even after Ramos's proposal (1482) for a newly designed hand accommodating the octave, images contained in a number of music texts displayed the inscriptions in ladder, rather than the customary spiral pattern. The controversy over the Guidonian system extended well beyond the Italian sources studied by Mengozzi. Ornithoparchus, for example, railed against the Guidonian system as too complicated, avoiding the image of the hand in his writing. Writers, such as the Swiss theorist Glarean, went back and forth on their dedication to the methodology. Many texts include hands that are smothered in marginalia, revealing readers grappling with an archaic system and a symbol that had more significance than a mere mnemonic aid.

In later chapters, Mengozzi is at his best as he examines the transmission of Guidonian theory through the writings of fifteenth-century theorists such as Johannes Gallicus, Ramos de Pareja — who proposed his own unpopular reform of the solmization system that ignited a firestorm of controversy — and Franchino Gafori. A comparison of a Bergamo manuscript draft of Gafori's Practica musicae demonstrates that the earlier version eschews the term “hexachord” and even goes so far as to question Guido's introduction of six solmization syllables against a pre-existing unit of seven letters. Chapter 8 focuses on Zarlino's borrowings from Gafori. The Epilogue adds a few familiar eighteenth-century figures as part of the author's contention that the Guidonian system morphed into something far from its original objective. It will be interesting to see if Mengozzi succeeds in convincing the scholars he criticizes.