"In November of 1999, I was one of four American composer/pianists - along with Philip Glass, Terry Riley, and Charlemagne Palestine - invited to perform at the 4 Pianos festival in Rome. We performed on four Steinway concert grand pianos, one for each of us, in the center of the high dome at the Palazzo delle Esposizioni, with the piano lids removed so that the audience could sit in a circle around us and the music could reverberate throughout the space. Both Terry Riley and I had our pianos tuned in our own unique and different versions of just intonation. The intensive experience of rehearsing and performing my own work, as well as hearing the music of my colleagues, was extremely inspiring. As the week progressed, I found myself contemplating the sonic effects that result from working with "commas" (two slightly different, mathematically precise versions of the same note). I woke up on the morning following the last concert with a radical new tuning in my mind. It came to me very clearly, seemingly with no planning or effort, with all of the mathematical proportions worked out in a well-balanced symmetrical configuration. It felt like a gift; however, I am aware that this moment could only have happened as a result of twenty years of working with just intonation tunings.

Upon returning to my music studio in New York City, I applied this new tuning to my customized "harmonic piano" and began composing a new work based on the tuning's unusual qualities. I have titled both this new composition and the tuning Revelation. As I experimented with the "revelation" tuning, I discovered that it possessed unique capabilities that I had never heard or encountered before. By combining carefully selected pitch relationships with various performance techniques, this tuning creates undulating waves of shimmering and pulsating sounds, with what sound like "phase shifting" and "note bending" effects and other acoustical phenomena. Sometimes the overtones are so audible that it sounds as if many different instruments are resonating from the piano. The tuning has so many beautiful and exotic sounds latent within it, that for the first few months, every time I played it, I discovered new harmonic regions and felt like an explorer in unknown and distant realms.

Revelation has twelve interconnected sections in various key centers. Originally, the main thematic material for most sections of the work was composed but the resonant tone clouds incorporated structured improvisation using a set of pre-determined pitch relationships, rhythmic patterns and ostinati to develop a complex sustained harmonic resonance with unusual acoustical effects. In order to optimize these effects I wanted to be flexible enough to vary what I was playing in response to what I was hearing. The exact nature of these effects would vary according to resonances of the instrument, the precision of the tuning, the acoustics of the performance space, and even variations in temperature and humidity. However, while working on a score that would enable pianists other than myself to play the work, I eventually decided to notate the tone clouds, with their complex, shifting rhythmic patterns. As I scored the work, I found that I could more fully develop the themes and material by writing everything out rather than leaving the development to the discretion of the performer.

I performed the world premiere of the original version of Revelation in July of 2001 at Germany's Klavier Festival Ruhr, followed by the U.S. premiere in October 2001 at Composers Collaborative's Solo Flights festival at Lincoln Center. The Grammy-nominated pianist Joshua Pierce gave the world premiere of the new complete version at New York City's Merkin Concert Hall in February of 2005. The final score, now almost 300 pages in length, is the culmination of my life's work to date.

The inspiration of the revelation tuning presented sonic opportunities that opened new vistas for me as a composer and performer. My hope is that I have created a work that is both rewarding to play and enjoyable to hear. In composing Revelation, I wanted to express my passion for harmonic resonance, and also create a work that would serve multiple purposes. Revelation retrains the ear for the world of just intonation, and the pulsating, shimmering sounds of the commas. The work presents an expanded harmonic, textural, and acoustical palette that may help lead to the next evolutionary step in tonality. The range and scope of pianistic techniques is also enlarged, thus creating a wider timbral spectrum. I believe that Revelation can be a springboard for other composers and performers to continue exploring the vast possibilities that are available when working with contemporary just intonation tunings and simultaneously sounding commas. I hope these elements will help return music to its ancient roots as a sacred art based on the science of pure tones and perfect mathematical relationships. – Michael Harrison