I intend in due course to reply to the long message posted by Jean Benabou on 30 October. Unfortunately I am very busy at present (I am lecturing six days a week this term) and I shall not have time to do so for a while. However, Jean's evident desire for a quick response from me on the subject of Proposition B1.5.5 in the Elephant cannot be ignored. Since I wasn't around at the time this result was first proved, I had to rely on the recollections of those older than myself as to its provenance: I am grateful to Ross Street and Bill Lawvere for their recent postings confirming the impression I received many years ago that Jon Beck had indeed had this idea in the late 1960s. It seems clear from their accounts that Beck had the idea independently of Benabou and Roubaud; which of them had it first seems impossible to establish at this stage. Since their work was independent, I should of course have credited Benabou--Roubaud as well as Beck at this point in the text of the Elephant, and I apologize for not having done so. The reason, I must confess, was that I had simply not come across the Benabou--Roubaud paper; clearly, this was a failure of due diligence on my part. Incidentally, in reply to a comment in Marta Bunge's posting, I did distribute draft copies of the Elephant to a number of colleagues, and invite their comments, before it was published. None of them picked up this particular point -- though I am not blaming them for that; the fault was of course mine. Regarding the fact that Celeyrette's thesis, and Jean's Louvain notes on "Les Distributeurs", are not in the bibliography of the Elephant, there is a simple reason for this: I decided at an early stage that, in order to keep the size of the bibliography within bounds, it was necessary to limit it to published books and papers, and to exclude unpublished theses and other articles circulated only in preprint form. (Hence also the absence of Beck from the bibliography.) I did relent in one or two cases (actually as a result of comments from one of the people who saw the drafts before publication) where a result appearing in someone's thesis, and not subsequently published, was specifically referred to in the text. Peter Johnstone