JK Rowling's own Potter book for sale

British author JK Rowling. Photo / Supplied

It marked the spellbinding start to the Harry Potter series of best-selling books which took the world by storm.

And now bestselling writer JK Rowling's own copy of the first edition of Harry Potter and the Philosopher's Stone is to go under the hammer.

Containing personal annotations and original illustrations by the author, the seven-part saga's first installment about a young wizard's adventures will be auctioned at Sotheby's in London.

Dr Philip Errington, director of printed books and manuscripts at Sotheby's, said: "This can undoubtedly be regarded as the definitive copy of any Harry Potter book.

"Not only is it a fine copy of a first edition of the first book, but the author has significantly personalised it with numerous written comments and many impressive and evocative illustrations.

"The personality of the author leaps from these pages and we are treated to a remarkable insight into her creative genius."

In one of the annotations, Rowling adds the words "changed my life forever" to the book's title.

She also questions whether a badger to represent Hufflepuff, one of the four houses at Hogwarts School of Wizardry and Witchcraft where Harry studies, was the right choice.

Rowling writes: "Perhaps Hufflepuff would have the respect it deserves from fans if I'd stayed with my original idea - a bear to represent it?"

Among the edition's original drawings is one of the orphaned baby Harry wrapped in blankets and left on a doorstep with a note.

After the first book was published in June 1997, the Harry Potter series went on to sell more than 400 million copies worldwide

It was transformed into a blockbuster film franchise starring some of British acting's finest talent and saw Rowling become what Forbes magazine described as "the first billion-dollar author".

The auction will take place on Tuesday.

- AAP