Aristotle's main physical treatise was one of the standard books which deeply influenced Western Science and philosophy. From the twelfth century onwards it was translated several times into Latin during the Middle Ages and it was read and commented upon constantly in schools and universities. Five medieval Latin versions have been preserved, two translated from the Arabic and three directly from the Greek. The Arab-Latin versions were made by Gerard of Cremona in the twelfth Century and Michael Scot in the thirteenth Century. The oldest Greek-Latin translation was elaborated by James of Venice in the first half of the twelfth Century: it is the first known Latin text of the Physics. It was revised by William of Moerbeke in the second half of the thirteenth Century. The third known Greek-Latin version, dating back to about 1200, is the anonymous and incomplete Translatio Vaticana, edited by A. Mansion in 1957; it is the only version published thus far in the Aristoteles Latinus series (Vol. II 2). The forthcoming edition will contain the Translatio vetus: this text basically goes back to James of Venice, but was known in the Middle Ages in different redactions. The edited text is that of our oldest and best witness: ms. Avranches, Bibl. mun. 221 (Af); the variant readings proper to other traditions, however, are also mentioned, both in the apparatus and the indices. The preface, written in French, gives a detailed description of the manuscript tradition and of the two main types of text it contains. It will also discuss the relation between the Physica vetus and the Physica Vaticana. A photo-mechanical reprint of the Physica Vaticana edition will be available together with the edition of the Physica vetus.