The mission of libraries consists of assuring the availability of coherent collections and the representation of different academic fields. For as long as paper has priority over electronics, the development of collections in their classic sense will keep its importance. The quality of service to the public is not determined solely by the presence of collections, but also by furnishing integrated access to academic information globally. The concept of the virtual library opens perspectives on the joint development of collections, notably those which concern electronic journals. Considerable savings will be possible thanks to the organization of consortiums and to access contracts for electronic information. The capacity to offer immediate access from any post will allow sharing of resources to be more in evidence than the pointed concern to conserve documents which has long motivated the joint development of collections.