Are there good introductory texts and intermediate monographs presenting categorical approaches to combinatorics and statistics? I know of and admire *Une théorie combinatoire des séries formelles* par André Joyal, cf. http://en.wikipedia.org/wiki/Combinatorial_species, but am seeking works which are in English, and that actually develop the mainstream elementary theory but using the categorical vernacular and results. Presentation of topics significant in computer science (cf. Knuth, Graham, Patashnik* Concrete Mathematics* for some examples of such topics) would also, of course, add interest. Best, Keith [For admin and other information see: http://www.mta.ca/~cat-dist/ ]