Porcacchi based his L'Isole piu famose del mondo (Venice 1572) on the most important geographical texts of the day. As a contribution to the linguistic history of non-literary texts in Italian, his compilation is presented here for the first time in a modern (part-)edition and evaluated in connection with its sources as a key text for the 'textual and lexical history of geography' with regard to (a) the conceptual history of geografia and geographic text traditions, (b) language-internal features and language-external contextualization, (c) techniques of intertextuality and comparative text-genre study. There is also a glossary of geographic terms and island names.