This book contains the invited papers of the conference “Algebraic combinatorics and extremal problems” held at the Université de Montréal from July 28 to August 2, 1986. This was the first time a conference focusing on these two subjects was held. The main reason for organizing such a meeting was that these apparently mutually distant parts of combinatorics are becoming more and more intertwined. This may be seen, for example, in the paper of P.J. Cameron bringing together - among other things - the representation theory of symmetric groups and the extremal problems of finite structures.

The conference proved quite useful in bringing together some of the best specialists in those two fast developing areas of combinatorics as well as others from related fields. All papers in the proceedings contain new results and most of them provide up-to-date surveys of the respective subfields accessible to non-specialists. There is a list of problems presented at the conference.

The organizers would like to use this opportunity to thank NSERC Canada for the financial support (provided by a conference grant) and the Université de Montréal and its Département de mathématiques et de statistique for hospitality. Finally we would like to thank Antoine Deza, Lucien Haddad and Marc Rosenberg for organizational help.