Dig through your old book collection because you could be sitting on a goldmine.
A first edition copy of Harry Potter and the Philosopher's Stone is set to go to auction in England with a starting bid of $50,000.
As fans of the series feverishly search to see whether their novel could be one of 499 rare copies worth thousands, appraisers are urging any would-be collectors to get in touch.
A spokeswoman for Berkelouw Books - a store which specialises in selling rare novels - told 7NEWS.com.au those who think they've got one of the remaining copies should get it appraised straight away.
She said one of the most commonly asked about books were from the Harry Potter series, with the business linking sellers to buyers at a weekly meet in Sydney on Thursdays.
To maximise profits, she said, selling privately could be better than going to auction because neither the buyer or seller pay premiums.
The obvious question is - how do you know if your copy is one of the elusive 500 worth thousands?
There are four telltale signs strewn throughout the world-famous pages of The Philosopher's Stone.
The first, ironically, is that "Philosopher's" is spelled incorrectly on the blurb.
A second typo on page 53 should see "1 wand" listed twice in Harry's equipment list for Hogwarts.
Then, the less exciting details - which includes the publisher on the title page being Bloomsbury, the author on the title page being "Joanne Rowling" instead of JK Rowling and the print line on the copyright page counting from 10 down to one exactly.
The lowest number in the counting indicates the edition number, meaning counting down from 20 to 17 makes it less valuable as its a 17th edition.
If you have any questions, appraisers say they are well experienced at identifying rare works of Rowling.