91�ȱ�

This Harry Potter book is no ordinary copy, it's what's called a first edition.

First editions are simply the first version of the book made available to buy.

This first edition of Harry Potter and the Philosophers Stone was bought second hand from a car boot sale for just £1 20 years ago.

Now it's expected to go for as much as £20,000.

First editions are often highly sought after by collectors because they are the closest they can get to the author's original draft of the book.

This copy is one of only 500 original editions, complete with spelling errors, it's also a little bit tatty.

The owner of the book, who did not wish to be named, bought it for about £1 whilst on holiday over 20 years ago and after reading it put it away in a drawer for years.

It wasn't until he asked a local book expert to come to value a box of books including the Potter book that its value was discovered.

"They weren't sure if it was a Harry Potter first edition but I soon established that it was thanks to some typographical errors that particular version is renowned for," book expert, Jim Spencer told the 91�ȱ�.

He went on to say "The one we've found is a former Staffordshire Library book which is stamped 'withdrawn from stock'."

The Harry Potter book will be sold on 31 July at Hansons' Library Auction in Staffordshire.