As part of National Library Week, Sarah Kennedy spends an hour exploring the treasures of one of the world's greatest collections of printed material - the Bodleian Library in Oxford. A haven for scholars since medieval times, the library takes its name from Sir Thomas Bodley who helped restore the existing library in 1598. At the moment, the Bodleian contains over five and a half million books stacked on 90 miles of shelving. The collection has been built up over centuries through gifts and bequests, but mainly through the library's right to receive a copy of every publication.