This is a hypertext English translation of Bénabou’s famous report Problèmes dans les topos; errors in translation belong to me alone. I have taken some liberties to ensure readability. Node numberings of the form 1.2.3 are guaranteed to be the same as in the source text; in places, I have introduced more granular node subdivisions than Bénabou; for instance, a subnode of 1.2.3 introduced in translation could be numbered 1.2.3·a. I have added titles to many sections in order to facilitate a useful table of contents.

The original French manuscript of Bénabou can be accessed here.