“The Door with Three Locks” is attractive, accessible, entertaining, fascinating, surprising and by turns exciting and cute. It is a great introduction to the astonishing subject of quantum physics. (Catherine Forrest)

Niko is a fourteen-year-old boy who, one morning, decides to take a different route to school and comes across a house he's never seen before. Drawn to the mystery, he enters the house and becomes immersed in a strange universe. Surprising things happen in the quantum world: a universe is created from nothing, a clockmaker's workshop offers journeys at the speed of light, and a cat appears and disappears at the same time. What Niko doesn't know is that he has a very special mission; luckily his new friends from this curious world are there to help him.
Sonia Fernández-Vidal emulates the mathematical adventure of 'El diablo de los números' and the philosophical teaching of 'Sophie's World' in this book, the funniest and most enlightening novel ever written about physics in our time, a novel that is destined to become a classic of educational literature for children aged 9 to 99.