It is not easy to know what criteria ought to be applied to designate a particular world musical tradition as of “major importance”, for we appreciate significance of many kinds. But from some time-honoured perspectives – compositional ingenuity, extensive and ancient historical trajectory, prestige and affiliation with literati in its own culture, a requisite high degree of musicianship and long training needed for mastery (to name a few) – the music of the Balinese gender wayang metallophone quartet, accompaniment to shadow plays (wayang kulit) and indispensable component of key sacred rituals, qualifies several times over. Other features make it an even more brilliant star in the musical universe, perhaps especially from a European stance. It is bona fide chamber music: intimate, richly polyphonic and full of mind-bending structural twists and turns lovingly attended to by generation after generation of its creators – a baffling sonic delight to outsiders, a mysterious spiritual labyrinth to devotees. Some observers have aptly compared it to the “learned style” of the string quartet; and one delights to imagine how enchanted Haydn would have been.

Since it happens to be from Bali, the genre has lured increasing numbers of international students in recent decades – hundreds or perhaps even thousands by now who have made the pilgrimage there to learn and practise and eventually disseminate it throughout the West and Japan. Nicholas Gray's extensively researched and information-packed work is the first book-length treatment of the subject in English, though not at all the first fruit of ethnomusicological researches: prior or contemporary studies by Colin McPhee, Henrice Vonck, Lisa Gold (especially) and others is copiously cited. Gray is one of many Balinese and foreign students who apprenticed at the feet of I Wayan Loceng (d. 2006), a brilliant, wry, demanding, and charismatic teacher, and generational heir to the historically crucial regional tradition of Sukawati village. Loceng either imperiously frightened off those unwilling to commit fully to his art, or else irrevocably transformed the lives of those who ventured into his force field. In writing a book such as this Gray had a duty not only to the traditions of ethnomusicology research and of gender wayang but, in a way, to the generous and restlessly probing intellect of Loceng himself, cherished by all who knew him. Loceng's mind was of course symbiotically shaped by the economy and patiently accumulated logic of the musical tradition into which he was born, which implicitly demands a commensurate response. The gauntlet is thrown.

Gray brings decades of study and expertise to the project. His reach is comprehensive but the focus is on musical structure and the range of viable approaches to composition and improvisation. This is inevitable for a music so steeped in abstract tonal designs. The heart of the scholarly project is encapsulated in his Table 5.1 (p. 94) which roughs out eight stages of a continuum from the musically fixed to the unfixed, from small “spontaneous variations” of existing compositions performed nearly verbatim each time to the birth of entirely “new pieces”. The latter is not a common occurrence in gender wayang, since aesthetics and compositional choices have been predetermined by a combination of historical precedent and the constraining 10-key range of the instruments. The future of the genre may thus be one of preservation rather than innovation, and the concluding chapter, by not suggesting any substantial new possibilities for the music, admits this by default.

The entire book can be seen as leading to and from 5.1's continuum. A series of preparatory chapters sets the scene, introduces the personages (numerous teachers besides Loceng), and describes the repertoire, elements, and technique. Subsequent chapters address each point on the continuum at length and from several angles, including copious staff transcription, the voluble comments of teachers and players, and the author's own analysis. The aim is to construct a multi-dimensional bird's eye picture of the music in several ontologies: the autonomous “work”, plus its imminent possibilities for variation. The discussion is extended, the detail impressive. The book's greatest asset is its large data set and the scrupulous sculpting of a nuanced portrait of improvisation. In this way, it significantly adds to our knowledge of improvisation's many manifestations in world practices.

But in the too-long core chapters 5 and 6, generalized description too often overwrites what should have been succinct theoretical exposition. We are presented with many, many examples, and much commentary on them, but no synthesis of what is right or wrong in the music that would allow us to assess its logic of construction. Ornette Coleman's credo for improvisation comes to mind: “From realizing that I can make mistakes, I have come to realize there is an order to what I do”. Any analysis of Coleman's music would thus have to explain his mistakes to shed light on his successes.

The key question might be: what can one not do in gender wayang, and how does this explain what one can? Overused qualifier caveats like “seems to” reveal an authorial reticence, and reliance on nebulous assessments like “overall feeling of freedom” (p. 99) and “letting go and allowing the music to flow” (p. 104) are, to this reader, a cop-out. Much is made of the importance of “Balinese accounts and understandings of themselves” (p. 246), which one emphatically endorses, yet the Balinese have (sensibly) never needed to take the metatheoretical view of their own music needed for a book like this. Musicians’ comments in these pages meander too much, and tend to boil down to a few basic points about freedom and flexibility – which are suggestive but insufficient for a penetrating musical analysis. More appropriate and ultimately respectful of their brilliance would be to elide indigenous voices with judiciously adapted technologies of Western music theory so that grouping structures, rhythmic and metric levels, tonal/contrapuntal procedures, and more could be explained more precisely. This is, of course, no disparagement, rather, it is an opportunity for two cultures each to bring to the table some of the things they do best.

Bravo to Nicholas Gray. But Loceng, as he was wont to do even with his best students, would gripe, scowl, proclaim humility, and ask more questions.