CATEGORIES DATABASE/TOOLS A C program for storage of and computation with finitely presented categories is now available as described below. The program is menu-based and stores finitely presented categories, functors between them and finite-set valued functors from them. The storage format is the same as that used by the Carmody-Walters `kan' program (available from the University of Sydney ftp site.) Several tools for computation with finite categories are included. For example, tests for equality of arrows, whether an object is initial and so on. A new implementation of the Todd-Coxeter procedure for computing left Kan extensions is complemented by an implementation of a procedure for computing right Kan extensions. Details are included in the user manual which may be found at ftp://sun1.mta.ca/pub/papers/rosebrugh/catuser.dvi The program was written by Michael Fleming and Ryan Gunther while they were employed at Mount Allison University under NSERC Canada's USRA program. It is free software and without warranty. Indeed, it should be treated as an `alpha' version. Bug reports (to rrosebrugh@mta.ca) are welcome, but may not be acted upon immediately. The source code and compiled (Sun and DOS) versions are avalable for ftp from the directory ftp://sun1.mta.ca/pub/sources/rosebrugh/{unix,DOS} The compiled versions are named category.exe. A set of examples is found in the `examples' subdirectories. Bob Rosebrugh <rrosebrugh@mta.ca>