Beyond the rows of shelves in many of Australia's libraries you can find ancient magic tricks, books on euthanasia and secret family histories — if you know what to ask for.

But at the National Library of Australia (NLA), in a padlocked room known as a giftschrank, lies the country's biggest collection of completely off-limits materials.

While it might seem odd in the age of the internet, the location of the room cannot be revealed.

It contains more than 200 books deemed not appropriate for public access, including unauthorised biographies, true crime and guides to euthanasia.

Behind the locked doors are copies of books on Schapelle Corby and Eddie Obeid that the courts deemed to be defamatory.

Director of Australian Collections Management at the NLA Alison Dellit said the collection also has text books and other materials that contained potentially dangerous errors.

"We do have material in here that accidentally recommended toxic combinations of chemicals be used for example," she said.

But she said it was important that the books were not destroyed, but kept for historical value.

"Part of the role of the library is to keep the history of Australian publishing and part of this history of publishing is that sometimes people publish things that shouldn't have been published," she said.

Books once banned, now acceptable

The term giftschrank comes from a combination of the German words for poison and cabinet, and such rooms have a long history in Germany.

When the Third Reich fell after World War II, much of the literature of the time, including Adolf Hitler's Mein Kampf, was stored in giftschranks rather than destroyed.

Keeping offensive books hidden away means that as society changes, material once deemed offensive can become mainstream.

At the Library of New South Wales there are currently no books in the collection completely off limits to the public, but that was not always the case.

Books once banned included classics like DH Lawrence's Lady Chatterley's Lover, John Steinbeck's The Grapes of Wrath and Mark Twain's The Adventures of Huckleberry Finn.

An Australian not-so-classic novel called Love Me Sailor was also on the banned list, after the author Robert Close was charged with obscene libel and spent three months in prison in Victoria in the 1940s.

The novel is about a woman on an all-male ship sailing between Chile and the US and includes the line:

"But he had no time for love-making. First he had to get the ship through the storm. "Then he'd come to her for his reward — even if it meant taking on the woman-starved crew, man by man!"

Restricted access: Family histories, pornography and magic

With the exception of Queensland, most states no longer have books that are outright banned in their collections, but they do have restricted-access material.

Books about euthanasia are commonly only available to library members over-18, as are sexually explicit materials — Puppetry of the Penis, a text on Russian tattoos and American Psycho fall under this category in Tasmania, for example.

In South Australia, the state library holds the papers of iconic Adelaide retail firm John Martin and Co, which was taken over by David Jones in the 1990s, who restricted access to the documents.

There is also a "suppressed" collection of 1970s printed pornography, purchased by the state library as a record of what was available at the time.

A number of states also carry collections related to the Indigenous population that are restricted according to the wishes of local communities.

Northern Territory has software which allows Indigenous communities to build and manage their own online collections — deciding for themselves who can access culturally sensitive material.

The State Library of Victoria has a magic tricks collection that can only be accessed upon request, and is not allowed to be publicly displayed.

The collection contains thousands of books, magazines, photos and posters, as well as detailed information on hundreds of individual magicians.

Dominique Dunstan said a person interested in finding the tricks of Houdini for example, could come across them, but it would not be easy.

"It might be a little bit of a search, you've got to want it, none of these sticky noses," she said.

If you have no luck in Victoria, the New South Wales Library also has a restricted-access collection of magic paraphernalia you could try.

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