 Categorical Myths and Legends - http://www.mcs.le.ac.uk/~ah83/cat-myths/ An archive of stories about category theorists. |
 Paul Taylor's Home Page - http://www.cs.man.ac.uk/~pt/ Includes papers on category theory. |
 Computational Category Theory - http://www.cs.man.ac.uk/~david/categories/ An implementation of concepts and constructions from category theory in the functional programming language Standard ML. Documentation and code. |
 Groupoids - http://www.bangor.ac.uk/~mas010/gpds.htm Notes by Ronald Brown. |
 Category Theory - http://plato.stanford.edu/entries/category-theory/ This expository article is an entry in the Stanford Encyclopedia of Philosophy. |
 Open Problems on Model Categories - http://claude.math.wesleyan.edu/~mhovey/problems/model.html Problems on model categories listed by Mark Hovey at Wesleyan University. |
 Categories Home Page - http://www.mta.ca/~cat-dist/ Web page for the category theory mailing list. |
 Descent and Category Theory Connections - http://north.ecc.edu/alsani/descent.html Maintained by M. Alsani. |
 Category Theory and Homological Algebra - http://www.math.niu.edu/~rusin/known-math/index/18-XX.html In the "known maths" series. |
 Groupoid Home Page - http://unr.edu/homepage/ramazan/groupoid/ Maintained by Birant Ramazan. Address book, open problems, meetings, pictures, other resources. |
 Categories, Quantization, and Much More - http://math.ucr.edu/home/baez/categories.html Introductory article by John Baez. |
 Toposes, Triples and Theories - http://www.cwru.edu/artsci/math/wells/pub/ttt.html By Michael Barr and Charles Wells, 1983. A revised and corrected version is now available free for downloading. Formats: DVI, PDF, PostScript. |
 A Gentle Introduction to Category Theory - http://wwwhome.cs.utwente.nl/~fokkinga/mmf92b.html Lecture notes by Maarten M. Fokkinga introducing some important notions from category theory, in particular adjunctions. Proofs are given in a calculational style, and the (few) examples are taken from algorithmics. The text is a long PostScript file. |
 CT Category Theory - http://front.math.ucdavis.edu/math.CT Section of the e-print arXiv dealing with category theory, including such topics as: enriched categories, topoi, abelian categories, monoidal categories, homological algebra. |