Author Tony Kerr has turned a bedtime story into an international seller.
The 41-year-old from High Barnes wrote Super Maxwell and the Last Heroes for his son Nathan so the youngster had something to read while waiting for the next Harry Potter book to come out.
Now the superhero story is selling copies around the world and Tony – who also has a daughter, Olivia, seven – is putting the finishing touches to the sequel.
"I wrote the book for my son, Nathan, and he really loved it when he was 12 and is still a big fan now he's 15," he said.
"The first Harry Potter books came out fairly close together and then there was a massive gap – we couldn't find anything he liked that was similar.
"I started writing a chapter a day and then reading it to him at night, then he'd tell me if he liked it or not – so it's rewritten quite a lot."
But Tony said he was not the first author to use his child as an editor in this way – even sections of classics such as Lord of the Rings were dropped because the author's children disapproved.
Super Maxwell and the Last Heroes tells the story of Maxwell Jones, who discovers that he and all of the children who live on the isolated island of Virporta have supernatural powers.
"The book is an exciting adventure that takes place across many different worlds," Tony said.
"Maxwell has to face monsters, dinosaurs, vampires, time travel, and even his own self from the future – but he still has to fit in his paper round at the end of the day.
"I loved writing it and hope it will be a success, as I would like to write some more stories about Maxwell and his adventures.
"I know it's already international because my friend in America has already bought a copy."
In the past Tony has had his plays performed at Live Stage and the People's Theatre, and broadcast on local radio, but Super Maxwell and the Last Heroes is his first book.
The dad, who works at Sunderland University, had his work published after it was voted as one of the most popular stories on the Arts Council-sponsored writers website YouWriteOn.com
"It wasn't chosen by publishers – it was chosen by people who were out there who read it and said it should be published," he said.
Tony celebrated his success by giving illustration and design student Phil Gibson the chance to have his work published by asking him to come up with the front cover.
Tony has already written the sequel to The Last Heroes and is editing it now. He is also working on a book about a boy who gets into problems when everything he writes comes to life.
Super Maxwell and the Last Heroes is out now, priced at 7.99, and is available in Waterstones, online at Amazon and at other bookshops.
Tony will be signing copies of his book in Waterstones in The Bridges on April 18, from 11.30am to 12.30pm.