The farm catalogue, which may once have hung behind the dunny door, is now sought after by one of Australia's major national cultural institutions.

The National Library in Canberra is gathering a variety of the catalogues for its ephemera collection.

Catherine Aldersey, who grew up on a farm, is responsible for finding the assorted brochures and booklets.

She says ephemera is what many would describe today as junk mail and includes catalogues which go back to the early 1900s.

"My favourites are the farming catalogues. There is something very spare about them, but at the same time they were pored over and kept, unlike today's junk mail which is designed to last a week or two," Ms Aldersey said.

Catalogues from a bygone era which were used to order farm machinery are a major part of a collection at the National Library in Canberra ( National Library Australia )

The catalogues were eagerly examined by farming families who only visited major town centres once or twice a year.

"A lot of these [catalogues] were made to last a whole year so people could see what was new on the market and order it remotely and have it shipped to them often on the train," Ms Aldersey said.

"A 1913 booklet which features chaff cutters is in excellent condition.

"A feature of the catalogue which demonstrates how well used it was at the time are two holes carefully punched through the booklet next to the spine.

Just one of the National Library's collection which shows how catalogues played a major part in Australian farm life ( National Library Australia )

"It was hung up by a bit of string. Probably hung on the end of a shelf. It has a wonderful cover, proudly announcing at the top that they are contractors to federal and state governments.

"A lot of them are painted and beautifully illustrated."

Parts of the collection have certainly seen better days and are now protected by plastic sleeves.

"Some of them come with insects living in them, with telltale nibble marks that mice or something have had a bit of a chew on it. Sometimes they have a bit of mould," Ms Aldersey said.

"[We] have a few that look as though they have been living in a woolshed for a few seasons."

People did really use them, so most have been well-thumbed, but that's an intrinsic part of their attractiveness as an evocative part of history."

A number of the catalogues relating to pasture improvement came with charts and have entries in pencil, where the owner has recorded what had been done on the property.

"They were designed as an information source as well as to sell products, so people would hang on to it."

With the passage of time, ephemera becomes rare and a bit more difficult to locate.

Library staff keep an eye on auctions and clearing sales and also on collectors.

"We also have very generous members of the public who think this material is important and share the value that we put on it and donate it to us," Ms Aldersey said.

So the next time you are in an outback toilet contemplating life and you notice a farm catalogue hanging by a well-worn piece of string behind the door, it may be just the thing that the National Library wants to get a hold of.