What is a National Art Library ? Many definitions have been proposed, but none has been really kept in. One cannot think about this to-day without having in mind the fortunes of the concept of nation at the end of this century. Can a National Art Library consider the art of only one nation ? The idea itself of a National Art Library is a passeist one. National frontiers have no meaning in art research. It is time for international bibliographical information network. But libraries have verry little imagination and a conservative understanding of their missions.