Quidditch Through the Ages to Find Them" have raised £17 million. In 2001, Rowling penned two companion books to the "Harry Potter series", "Quidditch Through the Ages" and "Fantastic Beasts and Where to Find Them", for British charity and offshoot of Live Aid, Comic Relief with all of her royalties going to the charity. As of July 2008, the books combined are estimated to have earned over $30 million for Comic Relief. The two books have since been made available in hardcover. Within the fictional world of "Harry Potter", "Quidditch Through the Ages" is written by Kennilworthy Whisp, a renowned Quidditch expert. In both
Harry Potter and Harry, Voldemort, and Hermione as playable characters. In 2017, Warner Bros. Interactive Entertainment opened its own Harry Potter themed game design studio, by the name of Portkey Games; before releasing in 2018, developed by Jam City. All seven "Harry Potter" books have been released in unabridged audiobook versions, with Stephen Fry reading the UK editions and Jim Dale voicing the series for the American editions. "Harry Potter and the Cursed Child: Parts I and II" is a play which serves as a sequel to the books, beginning nineteen years after the events of "Harry Potter and the Deathly Hallows".