Concerning Borceaux's citation of "Revised and reduced..." in the second edition of Bourbaki, Theorie des Ensembles, chapitre IV, I think a more accurate translation is "suppressed", rather than "reduced". What was suppressed from the first, 1957, edition of Structures was the 19 page appendix, titled Criteres de transportabilite, and devoted to giving useful criteria for verifying that a relation of a theory T, is transportable relative to a given typification, as these terms are defined in ΒΆ 1 of this chapter. Thus, this appendix also explains the concept of "transport of structure", a notion that Bourbaki employed frequently and also gives a rigorous definition of "canonical". It seems plausible that Chevalley was the author of this appendix, although Bourbaki tradition is to not confirm or deny such a statement. I have never understood why Bourbaki chose to suppress this appendix, as I find it very interesting and very well written. Bill Messing [For admin and other information see: http://www.mta.ca/~cat-dist/ ]