To avoid disappointment, an exhibition opening this week at the Cambridge University library should carry the warning sign: “These books contain no pornography”.



Despite undergraduate folklore there is no secret stash of pornography among the almost a million books in the 17 floors of the tower, which rises 157 feet above the library. The building, designed by Sir Giles Gilbert Scott, was completed in 1934 to mixed reviews, with the former prime minister Neville Chamberlain calling it “a magnificent erection”.

The legend was fanned by the fact that the tower was off-limits to students, though they could borrow from its collection when cataloguing began in 2006.



“We have no pornography – or rather we have none in the tower, we have plenty of pornography, all libraries have,” said deputy director Mark Purcell. “Ours is in a vault, under Arc – for arcana.”

The truth, revealed in the exhibition Tall Tales, is that as a copyright library Cambridge receives a copy of every book published in the UK. The tower was used by librarians to store “secondary material”, including Victorian and Edwardian children’s books, comics, dress patterns, cookery books, paper toys and board games, as well as paperback thrillers and bodice rippers – publications which they judged nobody would want to look at again.



Before being exiled to the tower, books were sometimes rescued from the shame of the secondary collection. In 1923, the librarian was invited to provide a reference in support of Radclyffe Hall’s The Well of Loneliness, when the lesbian romance was facing prosecution for obscenity. The letter from her publishers’ lawyers kindly offered: “In case you have not read Miss Hall’s book, we shall be happy to lend you a copy.” The librarian did not need to borrow a copy, but he did re-shelve the book among the arcana.



The public will be invited in for the first time on weekly guided tours over the summer. A member of staff recently used a head camera to record the winding concrete stairs, the books and views across miles of Cambridgeshire countryside: it took 20 minutes to walk from the top.



Many of the books have never been opened, despite the useful information they contain. The virgin copy of How To Be Happy Though Married urges: “The wife on her part ought not to be less desirous than she was in days of courtship of winning her husband’s admiration, merely because she now wears upon her finger a golden pledge of his love… Instead of lessening her charms, she should endeavour to double them, in order that the home may be to him who has paid her the greatest compliment in his power, the dearest and brightest spot on earth - one to which he may turn for comfort when sick of business and the weary ways of men generally.”



Some books in the exhibition are very valuable, including first editions of The Hobbit, Lord of the Rings, Casino Royale, and Enid Blyton’s Famous Five in mint original covers



“The ironic thing is that because we kept everything, no taste threshold applied, this collection is now of great interest to academics,” Purcell said. “We’ve had researchers working on childhood, education, industrial relations, manners – applications come in every week. But no pornography.”