This volume contains a medieval collection of Latin adaptations of Aesopian fables, the so-called Opusculum fabularum which consists of three books, each of them again containing about 50 fables. Its complete version has been handed down only in the Berlin manuscript Theol. lat. fol. 142. The critical edition of this text is the main part of the present volume. It also contains the critical edition of the text of those fables of the Opusculum fabularum that have been quoted by Conrad von Halberstadt in his Tripartitus moralium. The present volume is the very first publication of the Opusculum fabularum and will prove most useful for latinists, medievalists and other literary scholars in their studies of the development of the Latin fable in the Middle Ages and in early modern times.