Abstract

The current tendency towards the increase, change and definition of our information units is feeling the effects of a new implementation policy, one that is addressed to the user. In this article the information units are defined as Systems of Bibliographical Information (SBI), which means falling within the general theory of systems. An SBI is in this regard a group of elements that relate to one another for reaching a common goal or the mission of the library. These elements are the so-called primary characteristics of an SBI. In the article, we define these retroactive and mutually related characteristics. Users are the fourth element that define the system; they are considered by some today as the fourth power of our libraries. The way in which a user today approaches information is causing a change that goes from documentary analysis to the redefinition of the role of the librarian and which will inevitably influence the ways of use and the organization of our libraries or Centres of documentary resources, as they can also be called.