J.K. Rowling is launching Pottermore, a new website that will include new material and illustrations from the Harry Potter franchise.
The website will contain 18,000 words of footnotes to her Harry Potter books.
Pottermore, which will open to the public in October, will allow fans to read in-depth biographies of characters and other background material that the author was unable to squeeze into the original seven volumes.
Fans can register with the website at pottermore.com from this week, and in September a million of them will be given early access before the official opening date at the beginning of October, when the online shop will also open.
Fans will also be able to meet the Sorting Hat, which will ask them questions before assigning them to one of the houses of Hogwarts school, and learn which type of wand is best suited to them.
Rowling also said that she would be mounting a defence of the rules of Quidditch, the broomstick-based game that she invented, after fans complained to her that it is illogical.
The site will be free, but one of its main functions will be to provide a method for selling e-books and digital versions of the audio books, neither of which has been legally available before.
The official announcement, at the Victoria and Albert Museum in London, ends months of speculation about whether Pottermore would be a game or a new book.
A leaked memo by one of the four public relations companies connected to the project suggested that there was a treasure hunt element, but this was a marketing activity conducted when the website was first set up.
Rowling said that much of the material used on the site already existed but that she had not been able to find a place for it in the books.
“I would say that I had more than half of the new material already written or in note form. I dug some of it out of boxes, literally,” Rowling said.
“The world has kind of outstripped me, because in 1998 I had generated a lot more material than I could fit in the books.”
She was still considering writing an encyclopaedia of the Harry Potter universe, she added, but if she did publish one it would be a project for charity. Rowling hoped that the website would encourage more children to start reading.
Neil Blair, Rowling’s agent, said that the e-books would be straight transcriptions of the original novels without the additional material, but that there were plans to create a separate product next year that would combine both.
The website will initially have new material only for Harry Potter and the Philosopher’s Stone but footnotes and games will be added for the other books.
The new words for the first book will be presented in 44 “moments”, illustrations of scenes in the story drawn in consultation with the author. Users will be able to trace a mouse cursor over the images to discover hidden messages.
