The document discusses the purposes and uses of indexing in information retrieval systems. It defines indexing as constructing representations of documents to browse and maximize searching success while minimizing time and effort. Indexing facilitates reference to specific materials, acts as a filter for irrelevant information, and provides overviews of subject fields. The document then defines information retrieval as the selective and systematic recall of stored information. The purpose is to collect and organize information across subject areas. An information retrieval system consists of operations to index documents, store the resulting records, and retrieve them. It identifies six key functions: acquiring documents, analyzing content, representing content, coding indicators, storing documents and indicators separately, and developing and executing search strategies to disseminate results.