The Dictionnaire Étymologique Roman (DÉRom) presents the first attempt at etymologizing the ancestral vocabulary of the Romance languages since the publication of Meyer-Lübkes REW. Deviating from practices commonly accepted and applied in etymological research, the DÉRom adopts a method that has so far, due to the extensive documentation of written Latin, been dismissed as being little viable for Romance Studies: the comparative analysis of grammar, used to reconstruct proto-Romance lexemes. This volume contains some 250 articles, written and revised by 40 specialists in Romance linguistics based in twelve countries, as well as a detailed presentation of the theoretical groundwork of this project.