These comments start, as they must, from the text of I. Hilberg in the Vienna corpus.' This was the first properly critical edition of the Letters, and has not been superseded. It is, however, not without its limitations. In establishing his text Hilberg considered only a few MSS for each letter: for epist. 1, seven, and for epist. 107, six, in one of which (B) the letter is represented twice, though in neither case is it complete. Hilberg promised a volume of prolegomena and indices to accompany his text ;2 but it seems that he died before it could appear, and we do not know how he assessed his MSS, or how many he consulted before making his choice. What we do know is that those on which he relied form a very small proportion of those which exist. B. Lambert's catalogue of Jerome MSS3 lists 138 for epist. 1 and 145 for epist. 107, of which ten and thirteen respectively are dated ninth-to-tenth-century or earlier - and Lambert is well aware that his list cannot pretend to be exhaustive.4 Furthermore, there is some reason to doubt the accuracy of the collations which form the basis of Hilberg's edition.5 It is evident that much work remains to be done before a definitive edition can be produced. Meanwhile Hilberg's text is the best we have, and where I cite MSS I follow the readings of his apparatus criticus.6 The phrase 'the MSS' refers, in this article, only to those which Hilberg utilised.