This volume presents a new translation of Aristotle's Topics Book VI by Annamaria Schiaparelli, accompanied by a detailed commentary and textual notes providing insight into the history of the transmission of the text with its variants. In the Topics, Aristotle aims at developing his dialectical method. He introduces the four predicables (property, genus, accident, and definition) which are necessary for the classification and application of the topoi, or commonplaces. Book VI of the Topics is entirely devoted to the discussion of definition, the most extended and refined discussion of this subject handed down to us from the classical period. The concept of definition plays a central role not only in Aristotle's logic but also in his ontology. Issues connected with definitions emerge constantly throughout his works. Moreover, definitions are at the centre of Platonic philosophy and sparked a lively discussion in philosophy of the Hellenistic and late classical periods.