Two original draft artworks created for the Harry Potter books are expected to see some of the top bids in Nate D Sanders' latest online sale, which closes on March 27.
The watercolour sketches were created by British artist Cliff Wright, who was chosen to illustrate most of the Harry Potter books and characters, including Harry himself.
The first, a draft of the cover of 1998's Harry Potter and the Chamber of Secrets, shows the famous flying car scene that was later recreated in the movie release.
Dating to 1998 and annotated "please return Aw to: (undamaged)" and "For: Harry Potter shop display/ To: Rosamund Walker - Bloomsbury", it holds a minimum bid of $20,000.
Starting at $12,500 is the ink and watercolour cover art for the original 1999 Bloomsbury edition of the third book in the series, Harry Potter and the Prisoner of Azkaban.
Commenting on illustrating the series, Wright said: ''...a passage from the book was suggested and I began to draw ideas working closely with the publisher. So as to retain as much vitality as possible in the final watercolour painting I only produce small-scale quick pencil/pen sketches as roughs.
"Time is spent on character and composition but not yet on execution, so my roughs are very simple.''
As Nate D Sanders states, these roughs were produced at an advanced stage in the design process, and therefore show the almost-complete cover artworks.
In May 2013, a first edition of the first Harry Potter book, annotated and illustrated by JK Rowling herself, sold for ?�150,000 ($227,993), raising the world record for a Harry Potter book by 775%.
Paul Fraser Collectibles has a fantastic range of signed books and illustrations for sale.