With the passage of time things have been evolved from manual to automation and then integrated. The successors and versions of the cataloguing standards has come up with their enhancements alike AACR2 to Resource Description and Access. RDA is being developed to provide a better acceptability with object-oriented database structures. Today card catalogues are totally replaced with OPACs and now discovery interfaces are replacing OPACs. Discovery interfaces are also called next generation catalogs which give an enriched web based interface used by users including scholars and researchers. It also provides link resolver and an indexing, search and retrieval element. This paper discusses the discovery services and its development in the libraries and provides an overview of how libraries are using and take advantages of advance technology and make their resources easily accessible to the patrons through single search interface.