Dusko Pavlovic offers, in passing, several descriptions of category theory: Yes, category theory is the discipline of conceptual mathematics: it helps us extract the relevant structure and discard the contingent. Categories provide means for analyzing complex situations into conceptual parts. Categories are about understanding. We know how to respond to students who tell us that they understand the material but can't do the problems. So how does one respond to this? I would suggest that any branch of mathematics is justified finally only because it allows us to prove things previously unprovable. If we were restricted to doing things we understand I don't think we would have gotten very far. Indeed, the most conspicuous function of mathematics I know is that it allows us to do things we don't yet understand. In my experience the feeling of understanding doesn't come until after the problems are solved. And sometimes long after. I think there are strong cases to be made for the presence of categories in mathemamatics (beginning at least with the Adams operations). And I think there are good cases to made even for the _theory_ of categories in mathematics. But -- something none of us expected -- the best cases to be made for the theory of categories are not in mathematics but in applied areas. It is there that we are finding the refutation of Dusko's sad assertion "now when it has become clear that the dream of powerful, problem-solving category theory won't come true."