In 97 CE Julius Frontinus was appointed by the Emperor Nerva to the post of water commissioner for the city of Rome. In the De Aquaductu Urbis Romae he sets forth his duties, responsibilities and accomplishments during his first year in office. He sketches the history of the aqueducts, furnishes a wealth of technical data and quotes verbatim from legal documents. This edition is the first since 1922 to be based on the single authoritative witness discovered at Monte Cassino in 1429 and is also the first to take into account the idiosyncrasies of its twelfth-century scribe, Peter the Deacon, a man notorious for literary affectations of his own. R. H. Rodgers provides the first full commentary since the early eighteenth century, dividing his attention between text and language on the one hand and content and interpretation on the other.