“A harvester is a client application that issues OAI-PMH requests. A harvester is operated by a service provider as a means of collecting metadata from repositories”. Harvesting is an automated, regular process of collecting metadata descriptions from different sources to create useful aggregations of metadata and related services. The concept of harvesting has been developed in the context of processing of metadata. The concept refers to a technique of extracting metadata from individual repositories and collecting it in a central catalogue. Different metadata schema/standards, such as Dublin Core, Text Encoding Initiatives (TEI), Metadata Encoding and Transmission Standards (METS) and many others have been developed. Though every standard has been developed to suit a particular need, nevertheless, these can be used by others too. It becomes difficult for user groups to get access to the literature of different repositories following different standards. This resulted in the development of harvesting technology to facilitate search by the user groups. Metadata harvesting refers specifically to the gathering together metadata from a number of distributed repositories (e.g. eprint archives) into a combined data store.