It takes a keen eye to know what you're buying as a book collector, and while a first edition could be worth thousands of dollars, as the saying goes, you can't always judge a book by its cover.
Mistakes can be made when pairing books with dust jackets, potentially eroding collectors' investments, and one antiquarian book collector says it's a case of buyer beware.
"First-edition books are a great thing to get into if you want to put your money into something that you don't lose on, because there will never be more of them," says Andrea Boltresz, owner of Armchair Adventures in Robertson, New South Wales.
"Every year they continue to climb in value."
One example is Enid Blyton's book Five On A Treasure Island. First published in 1942, it's the most valuable in the Famous Five series.
"If there is anyone out there with a Five On A Treasure Island first edition, they should be really excited.
"And they should really look after it too, especially if it has its jacket with it."
Having been reprinted 40 times since its publication 80 years ago, Five On A Treasure Island has a multitude of book and dust-jacket combinations.
And that's where collectors can come unstuck.
Want to make a packet? Check the dust jacket
With about 10,000 books in stock, Ms Boltresz's business specialises in rare and fine bindings, plus vintage collectibles, and services private collectors who don't necessarily want to visit the shop to browse.
Instead, the business attends auctions on their behalf.
"We've found a lot of collectors of children's books, vintage children's books in particular, which is a huge area to collect in and very interesting," she says.
High-end collectors look for really pristine copies.
"If they are looking for a first edition, they are expecting that book to be the correct edition, with the correct dust jacket, and that dust jacket will be absolutely pristine, not a nibble out of it or a scratch anywhere," Ms Boltresz says.
"If it came originally with a dust wrapper, that's where the value is, and if you don't have the dust wrapper for the book, it will be worth significantly less than half what it would be otherwise.
"It's hard to find good copies that are really clean and still have dust wrappers that haven't been destroyed."
A 'mongrel set'
Ms Boltresz says her job never ceases to be fascinating.
"People leave things in books all the time; it's actually one of the great joys of being a second-hand book dealer."
While attending a Sydney auction, Ms Boltresz recently purchased 100 books, many of which included notes from the former owner about what they had done with the dust jackets.
"In this case, he's taken them off and put them on other editions because what he wanted to do was create a complete set of what looked like first editions, to sell as a set," she says.
"But … this person has inadvertently mixed up different editions with different dust jackets without realising what they were doing.
"Somewhere out there, someone has just bought a lovely set of Famous Fives that they think are first editions.
"But many of them can't be because we know the jackets aren't right as we have some of the books in our collection that belong to those jackets.
"They clearly understood that the dust jackets were valuable, but they've swapped damaged books for cleaner versions and haven't looked to see that it's exactly the same impression as the one that was originally with the jacket.
The wrong jacket with the wrong book means an $800 first edition is suddenly a $200 book, Ms Boltresz says.
So, can you judge a book by its cover?
Ms Boltresz says determining a book's value is easier than you think, once you know how to read the signs.
Ways of telling that jackets and books don't belong together include checking that the list of titles are in the same order and identifying different graphic styles, including font usage and page layout.
If the font on the cover is different from the page, that is an indicator too.
But Ms Boltresz says the most important thing is to do your research on a book before you go to buy … or sell it.
"Then you know that everything about it is represented clearly and people know exactly what they are getting," she says.
