Dog goes woof. Cat goes meow. Bird goes tweet, and mouse goes squeak...But what does the fox say? Ylvis started working with the illustrator for this book before they had even uploaded the video to Youtube as they felt it had the potential to become an interesting book as well. As they say "The level of detail in Svein's drawings make the book fun to read over and over. Hopefully kids will enjoy reading it as much as we enjoyed making it."