The Romance languages offer unique potential for empirical analysis and methodological innovation within the vast field of linguistics, due to the survival of a large body of historical documentation, the rich diversity of dialects and languages, and the exceptional quality of the research undertaken to date. However, these same factors have led to an ever-increasing volume of material available for study, requiring the establishment of a shared canonical knowledge base. This companion offers a balanced overview of the core subjects and the methodology which make up the field of Romance linguistics. It provides a solid foundation in the discipline as well as easy and convenient access to highly-specialised areas of research by means of systematic references to the latest handbooks and encyclopedias. The companion is designed to be read from cover to cover or to be consulted for information on specific topics. Advanced students, early-career researchers, lecturers, specialists of other languages, philologists, and historians alike will all benefit from this accessible and up-to-date reference work, as it enables readers to contextualise any knowledge of the discipline they may already possess.