They were deemed to be of no use to university academics, but now the hidden collection stashed inside Cambridges tallest tower has been exposed for the first time.
The imposing 17-storey tower at the Cambridge University Library has been used for over 80 years as a sin bin, where all material not deemed good enough for the main collection was stored.
But today a new exhibition celebrating the treasures of the tower has officially opened, granting the public access to the millions of books for the first time.
By law, the UL is entitled to have a copy of every book and journal published in the UK and Ireland, but those classed as non-academic were hived off into a tower.
The volumes, including children's literature, cookbooks, car manuals and novels, were not originally entered into the university's main library catalogue.
Liam Sims, rare book specialist at Cambridge University Library, said: "I suspect many academics didn't have any interest in this sort of material."
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He added that the items were "not deemed to be of academic use in a university library" but were "kept and preserved as part of the national printed record".
Many of the hundreds of thousands of items could only be found by using cards until an online cataloguing project, funded by the Andrew W Mellon Foundation, was completed in 2012.
"The Tower Collection is very much a bibliographical time capsule, the contents put out of sight and mind," said Mr Sims.
"Our cataloguing project showed that the collection is now treasured, and that its contents provide much interest for both the general enthusiast and academics, both in Cambridge and across the world.
"It is a treasure trove for researchers, and the collection tells the story of our national life through the printed word."
The tower had been the subject of much speculation over the years and had inspired authors from CS Lewis to Stephen Fry, even featuring in the latter's first novel The Liar.
Items in the tower include first editions of Casino Royale and The Famous Five, Mr Men cartoons and Victorian cookbooks.
But despite a long-standing student rumour that it includes a collection of Victorian pornography, the university librarians insist this is not the case.
Other highlights of the exhibition include the first novel to focus on poor, working-class black culture in Britain (Samuel Selvon's The Lonely Londoners) and an array of delightfully titled books such as Indoor Games For Awkward Moments and Cupid's Code (For The Transmission Of Secret Messages By Means Of The Language Of Postage Stamps).
Tall Tales: Secrets of the Tower runs until Saturday October 27.
It takes place in the librarys Milstein Exhibition Centre. Entrance is free.
The library is on West Road, Cambridge, CB3 9DR.