This volume contains the first critical edition and a complete English translation of the well-known correspondence conducted by the fourteenth-century 'sceptic' author, Nicholas of Autrecourt, with Bernard of Arezzo and a Master Giles. In the Introduction the extant manuscripts are analysed and the different positions of Nicholas, Bernard and Giles are discussed; the purport of Giles' reply to Nicholas is, contrary to common opinion, identified as a defence of Aristotelianism rather than of Bernard's 'sceptic' views. Two appendices contain the first critical edition of the records of the Avignon trial against Nicholas found in the Vatican Archives, and the "Condemned Articles" with an English translation. The volume is rounded off with extensive indexes, which facilitate the use of the book as a source for the history of fourteenth-century thought.