The main function of western musical notation is incidental it prescribes and records sound. But during the fourteenth and fifteenth centuries, notation began to take on an aesthetic life all its own. In the early fifteenth century, a musician might be asked to sing a line slower, faster, orbrstarting on a different pitch than what is written. By the end of the century composers had begun tasking singers with solving elaborate puzzles to produce sounds whose relationship to the written notes is anything but obvious. These instructions, which appear by turns unnecessary and confounding, brchallenge traditional conceptions of music writing that understand notation as an incidental consequence of the desire to record sound. This book explores innovations in late-medieval music writing as well as how modern scholarship on notation has informed--sometimes erroneously--ideas about thebrpremodern era. Drawing on both musical and music-theoretical evidence, this book reframes our understanding