> Elle repose sur le dos de quatre éléphants qui sont eux-mêmes sur le dos d'une tortue géante qui se promène dans le cosmos. >
(En passant, le texte de ce livre est disponible légalement et gratuitement sur le site d'un des auteurs: http://infolab.stanford.edu/~ullman/focs.html. C'est un des meilleurs livres de CS que je connaisse.)
Depends on what you qualify as "influential", but Jeff Ullman would definitely be pretty high up there in terms of most influential computer scientists.
He wrote some of the first (and widely accepted as some of the best) textbooks in introductory CS, databases, and compilers. The Dragon book is still one of the most-used compilers textbooks today. The only other books that I can think of off the top of my head that were as cutting-edge (for their time) and as widely used are K&R and SICP.