Paul Taylor's Home Page - Includes papers on category theory.

Categories, Quantization, and Much More - Introductory article by John Baez.

Applied and Computational Category Theory - A brief description of category theory, and some useful links.

The Computational Category Theory Project - The aim of the project is the development of software on a wide variety of platforms for computing with mathematical categories and associated algebraic structures.

Category Theory and Homological Algebra - In the "known maths" series.

A Gentle Introduction to Category Theory - 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.

Categorical Geometry Homepage - This site contains online books and research papers on the subjects of categorical algebra, categorical logic, categorical geometry, lattice theory, universal algebra, algebraic geometry.

Structures Directory - Email directory of logicians, algebraists, and programming linguists working primarily on structural problems in mathematics and computer science.

Category Theory - Directory and resource site.

Toposes, Triples and Theories - By Michael Barr and Charles Wells, 1983. A revised and corrected version is now available free for downloading. Formats: DVI, PDF, PostScript.

Descent and Category Theory Connections - Maintained by M. Alsani.

Open Problems on Model Categories - Problems on model categories listed by Mark Hovey at Wesleyan University.

Computational Category Theory Project - The aim of this project is the development of software on a wide variety of platforms for computing with mathematical categories and associated algebraic structures.

Categories Home Page - Web page for the category theory mailing list.

Categorical Myths and Legends - An archive of stories about category theorists.