Fans of the Harry Potter series are leaving notes for the next generation of readers to find.
Fans are writing messages in the books to say exactly what the books meant to them.
Harry Potter website Mugglenet.com encouraged fans to sneak the notes into library books and donated books and share them pictures of it on social media using the hashtag #PotterItForward.
With over 450 million copies sold, Harry Potter is the best selling book series of all time.
It topped a Facebook poll last year as one of the most influential books in the world, beating Harper Lee's ''To Kill A Mockingbird'', J.R.R. Tolkien's ''The Lord of the Rings'' and even the Bible.
Even though the final book "Harry Potter and the Deathly Hallows" was published in July 2007, the series still continues to bring together audiences across different age groups and social and ethnic backgrounds, as evident in #PotterItForward.
In a study called “The greatest magic of Harry Potter: Reducing prejudice,” psychologists led by Loris Vezzali at the University of Modena and Reggio Emilia in Italy, say that reading “Harry Potter” improves attitudes toward stigmatised groups, such as immigrants, gay people and refugees.
Rowling's world of wizardry was filled with stigmatised characters who struggled due to circumstances out of their control.
The “muggles” were deemed inferior due to their lack of magical powers. The "half bloods" or "mud bloods" - wizards and witches descended from only one magical parent - didn't get much respect either, while Lord Voldemort believed that power should be held by "pure blood" wizards only.