, the fourth volume in Lucy Hawking's series about a boy named George, who travels into space and has adventures based on real science.
The successful series has been translated into 38 languages and is something of a family business, with Hawking Snr acting as co-author. The books introduce scientific concepts such as black holes and DNA, and explain them in easily accessible mini-essays written by Stephen Hawking and other leading academics.
But Hawking says her father's involvement goes beyond contributing essays. "He reads everything and comments on everything and makes a lot of suggestions," she explains.
The idea to write a book had been on her mind for a while, she says, then the eureka moment came at a children's party. "All the little ones were gathering around my dad," Hawking remembers. "One boy asked my father: `Stephen, what would happen to me if I fell into a black hole?' And my father said: `You would be turned into spaghetti.'
"The fact that dad gave that answer and the kids were so pleased with it, I thought: `This is the genesis of the project.' "
She adds: "I grew up with science. It was always there. Some kids don't have that. This is something I wanted to share."
But Hawking insists that any lack of interest on the part of some children is not the fault of their teachers. "All the science teachers I have ever met do a fantastic job. They are trying to reach out to their students and engage them."
Hawking adds that misconceptions about scientists cause many children, particularly girls, to fail to see the attraction of a career in physics or chemistry. She says that young people can sometimes think of scientists as loners with "massive heads, lab coats and four pairs of spectacles".
Working with her father has been fun and has given Hawking a new appreciation of just how vast his knowledge is. "I always knew he had a phenomenal memory bank," she says. "But it has just been staggering to see how much he knows."
The books take on topics that are far from simple, from the Big Bang and space exploration to computer hacking. But Hawking admits that some topics are just too complex to be included. "It would be a mistake to think you can simplify everything. Some things are just so phenomenally complicated, if you simplify them they would be meaningless," she explains.
Contrary to what people might assume, however, it is not Hawking who has to rein in her father. "He is much more likely to say I have overcomplicated something, rather than the other way round," she says. "He is all for simplicity."
To introduce George and the Unbreakable Code before it is published next month, Lucy Hawking is taking part in a free, live webcast with Scottish Book Trust on 22 May at 11am, which will be accessible to teachers and their classes all over the UK. The event, funded by Creative Scotland as part of the 2014 Cultural Programme, will feature Lucy Hawking exploring the scientific theories behind this book and the three previous instalments in the series.