The same thing can be identified by many different terms, and the same term may mean many different things. - Douglas John Foskett

Information retrieval consists of four main stages: Identifying the exact subject of the search; Locating this subject in a guide which refers the searcher to one or more documents; Locating the documents; Locating the required information in the documents.

In 1948, it was agreed that a study of classification should be made, and a committee of scientists was appointed under the leadership of Professor. J. D. Bernal.

Douglas developed a strong interest in the relations between education and classification. He explored the writings of L.S Vygotsky, L. von Bertalanffy (for systems theory), and J.K. Feibleman and wrote a number of articles on classification and integrative levels.