The intention of this book is to investigate the role that St. Jerome played as a translator and his effect on translation. In order to achieve this intention, one of the most significant works that St. Jerome wrote is his letter to Pammachius "On the Best Method of Translating" is going to be used as the main document for investigation in this book. This letter is originally written by St. Jerome to defend himself of the charges that were brought against him regarding his translation in general, and his Vulgate in particular. Looking at the history of translation theory gives bases for comparison and demonstrates whether translators are making progress or just repeating the same mistakes. It also helps to assess whether modern theorists are saying something new or simply repeating the same ideas in different language.