So there are 3 Harry Potter novellas/short stories
September 6th - Ebooks only as of now
promise to tell of Rowling's inspirations for characters and places in the world of Potter's novels.
Power, Politics And Pesky Poltergeists, which gives "a glimpse of the darker side of the wizarding world", including the history of Azkaban prison. It tells the life story of Professor Umbridge and the friendship between Tom Marvolo Riddle and potions master Horace Slughorn.
Next is Heroism, Hardship And Dangerous Hobbies. It tells the stories of heroic characters including Remus Lupin and Minerva McGonagall, as well as Sybill Trelawney and Silanus Kettleburn.
The final book, Hogwarts: An Incomplete And Unreliable Guide, tells the history of the school which Potter, Hermoine Grainger and Ron Weasley attended.
The books are available for pre-order now. It doesn't appear there are print editions of the collections.
Source: http://www.nme.com/filmandtv/news/three-new-harry-potter-books-by-jk-rowling-are-bei/414972#HwRyugw0AHKUGoBW.99
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