Da Vinci Code the writing that can be backward and uside down it was on beginning of chapters?

You're thinking of the "Solvitur Ambulando" inscription that appears at the beginning of each chapter in Dan Brown's *The Da Vinci Code*.

The inscription is a Latin phrase meaning "It is solved by walking." It's written in a special font that can be read both forwards and upside down, a characteristic of the book's focus on cryptography and puzzles.

Let me know if you'd like to learn more about the Da Vinci Code or any other book!