Next week’s post on Beginning Mathematical Logic will be more exciting (promise!) — an all-new chapter on intuitionist logic. But before we get there, here is the revised chapter on set theory. Again, I have done some minor tidying since the last edition, but there is no real novelty, as I’m currently reasonably content with the chapter. But I’m sure that doesn’t mean it couldn’t be improved — so, as always, all comments gratefully received.