I start from two premises: first, that musical notation provides a powerful tool for the recording, preservation and communication of music; and second, that memory and the combination of oral and aural traditions are equally powerful tools for the same purposes. In this paper, I explore the impact of musical literacy, the act of reading musical notation and translating it into sounding music, on musical practice, and how that impact has affected musical practice in Western traditions. Part of the problem is a question of which is the chicken and which the egg. Does prevailing musical practice demand developments in musical notation, or do innovations in notation drive innovations in musical practice? Have musicians from different eras and traditions viewed and exploited the relationship differently? Does musical literacy enable or limit musical practice?