TAC Special Volume, Call For Papers Dear Colleagues, Among the many important events which occurred in 2002 was the 60th birthday of Aurelio Carboni. With the approval of the Editorial Board of Theory and Applications of Categories, we wish to honour our friend and colleague Aurelio with a special issue of TAC. Following the editorial policy of TAC, we welcome papers that significantly advance the study of categorical algebra or methods, or that make significant new contributions to mathematical science using categorical methods. Authors are invited to submit their manuscripts in electronic form to any of the Guest Editors no later than September 15, 2003; articles will appear as soon as they are accepted. Authors are asked to prepare their manuscripts following the author information described at http://www.tac.mta.ca/tac/authinfo.html All papers will be carefully refereed following the standards of Theory and Applications of Categories. Guest Editors: George Janelidze george_janelidze@hotmail.com Steve Lack stevel@maths.usyd.edu.au Bill Lawvere wlawvere@buffalo.edu Enrico Vitale vitale@math.ucl.ac.be Richard Wood rjwood@mathstat.dal.ca