Los servicios de información. Un acercamiento a su evolución.

This paper, which is a bibliographical review, sets out the theoretical aspects related to information services, evolution, their assessment, information services and their relation to human resources. Also, the advantages of the evaluative process are presented, taking into account that users' needs constantly change, so it is indispensable for the specialists working at information organizations to research them systematically. [ABSTRACT FROM AUTHOR]