This book provides a complete, comparative, non-gallocentric account of nasality across all the Romance languages, and demonstrates the central role which vowel nasalization has played in the history of sound change in this family of languages. It assembles a large amount of important philological and linguistic data previously dispersed and often difficult to access, organizing it in a way which allows a clear and revealing analysis of the developments examined. This will be the standard work in its field for many years. It will be of central interest to linguists and philologists of Romance, as well as to those concerned more generally with understanding the causes, patterns, and processes of sound change.