For the first time, an author is top of the fiction and non-fiction charts. So who is Conn Iggulden?
Chart topper Conn Iggulden
Not so long ago, the name Conn Iggulden was not one associated with making bookselling history. The 35-year-old father-of-three was not a star name among authors, but all that has now changed.
The Dangerous Book for Boys was one of 2006's bestselling books. It struck a chord with its sense of adventure in teaching young readers about catapults, go-karts and bows and arrows.
It is still number one in the non-fiction charts, and its bestselling counterpart at the top of the fiction charts is by the same author.
Wolf of the Plains is the first of a new series about Genghis Khan, which underlines how Iggulden likes his fiction to be rooted in history. Julius Caesar was the subject of another series which has many devoted fans.
He is not the only writer to cross the divide between the two genres of writing. John Grisham has published his first work of non-fiction, and Jeffery Archer followed up his own thrillers with his prison memoirs.
Here, the Magazine puts some questions to Iggulden.
How do the skills required for fiction and non-fiction writing differ?
The biggest difference is that in writing The Dangerous Book, I could put a chapter to bed and move to a completely new subject.
With fiction, you have to hold the entire book in your head at all times, which is harder, I think.
With non-fiction, my brother and I wanted to make everything ourselves, so we would know the pitfalls.
It wasn't as purely creative as writing fiction, but the pleasure came from learning new things every day.
The Dangerous Book for Boys was a sudden success to a new market. How did the exposure affect you?
Every year, my dentist asks me what I do for a living. Every year I tell him and he forgets. This time, he knew The Dangerous Book.
He'll probably forget next year, but it was a nice moment. The Dangerous Book was taken up by a number of national newspapers, which hadn't happened to me before.
Play in the old-fashioned way
Suddenly, there were reviews all over the place, the Telegraph cartoon was about the book and the Times even included Dangerous posters. It was a great summer.
Some papers said it helped boys to emerge from their molly-coddled world and into a more adventurous one. Do you agree?
I hope it's true! I think the book became part of a swing against some of the sillier aspects of "health and safety" and the Playstation culture. The swing was happening anyway, but it is brilliant to be part of it.
Your historical novels have centred on what you describe as "self-made" men like Julius Caesar and Genghis Khan. Which 20th Century British figure would be ripe for the Iggulden treatment?
Every century has its heroes, thank goodness. Some of them, like Douglas Bader or Joe Simpson, have already been filmed or written up. Their stories are as good as any you'll find.
There aren't many with the impact of a Caesar, but individual stories of courage are still there.
My brother Hal once caught a rapist and received a bravery award for bringing the man to justice. In other words, it doesn't have to change continents to be important.
With your experience in the classroom, what reforms would you make to the education system to make literature more accessible to children?
I'd bring back grammar from a young age. I used to use textbooks at A level that were originally designed for 14-year-olds. That's pretty sad.
If I know one thing, it's that people who know the structures of language take enormous satisfaction and pleasure from that knowledge.
To deny it to generations out of some soppy philosophy is just daft. We've tried making school easier and it doesn't work.