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: