«Concerning the Great and the Small» is a little-known philosophical work by Theodoros Prodromos, an outstanding Byzantine writer of the 12th c. The object of the present paper is to analyze the style and the structure of this little essay of Prodromos, to define the specific features of rhetorical and logical argumentation represented in it. It is demonstrated, that «Concerning the Great and the Small» is an interesting example of logical argumentation, which is built to argue that the notions of the Great and the Small do not refer to the category of relation, but the category of quantity and that they are the contrary notions (τὰ ἀντικείμενα). It is emphasized that this interesting text of Prodromos requires a detailed investigation in the context of the history of logic in Byzantium.