The Rilloby Fair Mystery : Barney Mysteries #2

Barney, Roger, Diane and Snubby love solving mysteries, with the help of Loony the spaniel and Miranda the monkey.Rare and valuable papers have been stolen from collections kept in secure rooms with locked doors and barred windows. How does the thief escape without a trace, and when will be strike again? Could there be a connection with the fair travelling around the area?