I translated St Jerome’s prologue to the Gospels several years ago, as part of a project involving the Eusebian canon tables. That translation is here, and a page leading to my information on the canon table system is here. I’ll revisit that translation when I edit the others for consistency. Not right now though. This prologue to the Gospels is the last by St Jerome. That prologue written as an introduction to the Letters of Paul is not by him, as he seems never to have translated or edited any translations of Paul’s Letters. I’m working on that one right now, and it’ll be posted next. It’s the last of the prologues preserved in the Vulgate.
[See also the final draft version of this translation, on this page]