Three Recitations on Holonomic Systems and Hypergeometric Series

These "recitations" were given in the 24th session of the "Seminaire Lotharingien", held in the Spring of 1990, somewhere in the Vosges mountains. I thank Dominique Foata for inviting me, and letting me sample one of these charming seminars which preserve the spirit that Oberwolfach lost a long time ago. I would like to thank Peter Paule and Voker Strehl for the invitation to include them in this special issue of the JSC, and for many helpful comments.