The Dominican friar Iacopo da Cessole (13th. – 14th. century) wrote the Libellus de moribus hominum et de officiis nobilum ac popularium super ludo scaccorum based on a collection of sermons preached to the laics. The treatise contains descriptions of the pieces beginning from the king and then continuing with all the nobles pieces and the eight pawns, each identified according to a trade. Iacopo describes each piece in detail and uses some short stories (exempla) to illustrate the vices and the virtuous behaviour of each piece. The fourth book contains an explanation of game’s rules that allow to have a civic order in an Italian Commune in the first years of the fourteenth century. The work was a great success: more than 250 manuscripts of the Latin text have been preserved and during the fourteenth and fifteenth centuries it was translated in numerous languages. Italian vernacular translations are attested from 27 manuscripts and two old prints. This book provides a general introduction to the work of Iacopo da Cessole, the critical edition of one of the versions of the Tuscan vernacular translation of the fourteenth century, based on all known manuscripts, and a detailed analysis of the exempla and of the numerous citations from classical and medieval works contained in the text. This version of the vernacular translation is till now unpublished, because the old prints and the print of nineteenth century (Ferrario 1829) were based on a different version.