This volume contains the first critical edition of Matthew of Orléans' Sophistaria, dating from the first half of the thirteenth century. The genre is closely related to the Syncategoreumata-treatises and Sophisma-collections, which all deal with logico-semantic problems, but each in a different way. The Sophistaria-treatise takes commonly used logical, semantic and grammatical distinctions as its starting point and subsequently moves to the discussion of puzzling sophisma-sentences these distinctions are exemplified in. The volume contains a broad introduction, as well as extensive indexes of names, sources (loci), subjects, and sophisma-sentences.