Abstract
This informal paper tries to motivate the use of category theory in computing science by giving heuristic guidelines for applying five basic categorical concepts: category, functor, natural transformation, adjoint, and co limit. Several examples and some general discussion are given for each concept, and a number of references are cited, although no attempt has been made for completeness. Some additional categorical concepts and suggestions for further research are also mentioned. The paper concludes with a brief discussion of some implications for foundations.