In today's digital landscape, we have the luxury of experiencing music anytime, anywhere. But before this instant accessibility and dizzying array of formats--before CDs, the eight-track tape, the radio, and the turntable--there was only one recording technology: music notation. It allowed singers and soloists to travel across great distances and perform their work with stunning fidelity, a feat that we now very much take for granted.

Thomas Forrest Kelly transports us to the lively and complex world of monks and monasteries, of a dove singing holy chants into the ear of a saint, and of...