A while back, I constructed a webpage linking to online materials on category theory at an introductory/middling level, including lecture notes, (legally available!) books, and videos of lectures. You’ll find it at https://www.logicmatters.net/categories/ I initially wrote this really for my own use, to keep track of things I found. But the page has got over 25K visits in the last year, so obviously some others are finding it useful too. I’ve had another non-categorial project recently, so haven’t been giving this page much attention. However, I’ve just now updated it, removed a couple of dead links and corrected some others. But please do let me know of appropriate recent materials I should be adding to the list — and spread the word to students who might find it useful. Peter Smith [For admin and other information see: http://www.mta.ca/~cat-dist/ ]