It’s the dream isn’t it? Discovering you actually own a first edition that has quietly been sitting at the back of a shelf or the bottom of a box, collecting dust and value.

In April this year we reported on a first edition of Harry Potter and the Philosopher’s Stone, signed by J.K. Rowling, selling for £68,800 ($90,000) at auction. Two months, later, another first edition has come out of the woodwork and has been valued at £20-30,000 ($16-$24,000).

Before you get super excited and start rooting through your bookshelves, the likelihood of owning a first edition is rare.  Jim Spencer, a book expert at Hansons Auctioneers was the one to discover the new find’s true worth. He said, as reported by Ben Waldron at The Derby Telegraph:

“I was called to a client’s house just over the border in Staffordshire to value three boxes of books and there it was—the holy grail of Harry Potter books.

“I was so excited. Every book valuer dreams of finding one of these.

“I was slightly caught in disbelief when I first saw it. I receive a few calls every week from people saying they have a first edition Harry Potter, and it can invariably be ruled out in seconds, or it’s one of the titles from later in the series when production was huge because of its success.

“The one we’ve found is a former Staffordshire Library book which is stamped ‘withdrawn from stock.”

The book owner is a fifty-four year old office worker, who wishes to remain unnamed. He said on the valuation:

“I bought the book along with three or four others to read on holiday about 20 years ago.

“I thought nothing of it at the time. I read the book, in fact I’ve read all the Harry Potter series, and then put it away in a cupboard for years.

It’s so exciting to think that a holiday read could be worth so much now. It might raise more than enough money to buy a nice new bathroom.”

That’s going to be one fancy bathroom.

So how do you know if you have a first edition? The first British printing by Bloomsbury back in 1997 produced only 500 hardbacks, 300 of which went to libraries, and contains a print line that reads 10 9 8 7 6 5 4 3 2 1 and the crediting of Joanne Rowling rather than J.K. US first editions of Harry Potter and the Sorcerer’s Stone have the number line  1 3 5 7 9 10 8 6 4 2 8 9/9 0/0 01 02 on the copyright page along with ‘Printed in the U.S.A.23’ and ‘First American edition, October 1998′ and could fetch up to $6,500.

If your dreams are slowing fading, don’t give up hope yet! AbeBooks’ handy Guide to Collecting Harry Book Books illustrates that first editions, deluxe editions and signed editions could be all worth more than you think, from £200 up to four figure sums. A copy of Harry Potter and the Philosopher’s Stone believed to contain Daniel Radcliffe’s first autograph owned by a woman who was an extra in the film in 2000, has just been sold for £2,600.

The newly discovered first edition will be sold at Hansons’ Library Auction at Bishton Hall, in Staffordshire on Wednesday 31st July.