Hardy and Corrall (2007) add that a subject librarian can also be by faculty liaison and communication onto the definition of the subject. Though the definition of a subject librarian is quite normative, Hardy and Corrall (2007) have argued that the more a library is highly specialized, the greater the amount of time that will be spent by academic librarians in subject support.  Rodwell (2006: 49) claims that a major reason for establishing subject librarianship lies in the fact that faculty identify with their subject relate best to library staff who understand and share these values. Because the subject librarian acts as a link between the library and faculty, and between the student and library and between the library and the wider world of information (Dale, Holland, Matthews, 2006: xv), several authors (Rodwell, 2006) agree that the subject librarian performs roles of: