JK Rowling is releasing three new Hogwarts-themed e-books next month.

The three titles in the Pottermore Presents range will bring together new stories and first-person reflections on the wizarding world from the Harry Potter author as well as writings already published on her Pottermore website.

Short Stories From Hogwarts: Power, Politics And Pesky Poltergeists offers "a glimpse into the darker side of the wizarding world, revealing the ruthless roots of Professor Umbridge, the lowdown on the Ministers for Magic and the history of the wizarding prison Azkaban."

There will be new writing about Horace Slughorn's early Hogwarts teaching career and his relationship with Tom Marvolo Riddle, plus on Philosopher's Stone baddie Quirinus Quirrell.

Professors Minerva McGonagall and Remus Lupin, two of the books' best-loved characters, will be profiled in Short Stories From Hogwarts: Heroism, Hardship And Dangerous Hobbies, with never-before-published work on Professor McGonagall's role in the second wizarding war.

This magical tome will give "a peek behind the closed curtains of Sybill Trelawney's life" as well as introducing readers to "the reckless, magical-beast-loving Silvanus Kettleburn along the way".

Hogwarts: An Incomplete And Unreliable Guide will bring the school of witchcraft and wizardry alive.

It promises to help you "venture into the Hogwarts grounds, become better acquainted with its more permanent residents, learn more about lessons and discover secrets of the castle... all at the turn of a page".

Pottermore CEO Susan L Jurevics said the e-books will "supplement the Harry Potter book series" and are easily able to be read in an hour.

She said: "The e-books will delight readers as they take them beyond the Harry Potter stories and deeper into the wizarding world.

"JK Rowling's writing in these collections reveals intricate details of her characters' lives, their histories, as well as her inspiration."

Rowling's last Harry Potter novel was published in 2007. The script for her new stage play The Cursed Child became the fastest-selling book in a decade in the UK on release on July 31 this year.

The three e-books are available to pre-order from Pottermore and digital book retailers for £1.99 each and will be published on September 6.