Information institutions are those that have, or share in, the mission to preserve, conserve, and disseminate information objects and their informative content. We think of institutions, often, as associated with their physical presences—usually in the form of great buildings or campuses. But an institution is more than its housing.

It is an organization, perhaps even a sort of organism, in which all of the parts work together even in often inordinately discrete roles, not only to achieve a common goal but also to contribute to the vitality and therefore the ongoing life of the central institution. This quality is shared by all manner of institutions, from central banks to supreme courts to universities and so on. Information institutions frequently are described as systems—a system is a series of discrete functions that aid or impede one another—information institutions have inputs, outputs, and internal communications that keep them functioning. An essential aspect of any system is ongoing unimpeded communication among the components. If at any point communication breaks down, the whole system fails.

According to various scientific justification, we can distinguish several basic formulations of library functions: first of all is its social function, followed by its archival function, and information function, educational function, function of a public defender and distributor of knowledge and information (which partly overlaps with the informational and educational function), cultural function and extremely interesting and less often in the Bulgarian libraries therapeutic function. Now we’ll make a short characteristic of all library functions as follows:

- educational function — to