Information retrieval describes the scientific methods, processes, and procedures that are used in the retrieval of recorded data in files and databases. This science covers the overall search activity that seeks information in a document (including text and images), the document itself, or the metadata within a document. This type of unstructured material (often in text-based documents) is usually found in full-text databases. Many modern libraries and archival storage centers use information retrieval software that serves to organize, store and retrieve data and information from document sites and article repositories. When searching for particular data or information, a user can search for this information using full-text or content-based indexing tools.