Books are disappearing from the library in Valleby. How is that possible? After all, the library has had an alarm installed. Lasse and Maja are facing a difficult case!

Martin Widmark and Helena Willis bestselling The Whodunit Detective Agency series has sold over 12 million copys worldwide. Meet Lasse and Maja, who runs a small detective agency together, in a series of puzzling mysteries for primary school readers. The stories are set in and around the small town of Valleby, and have a rich gallery of characters to be captivated by on the exciting road to solving the mystery.

The Library Mystery is the thirteenth installment in the series with Lasse and Maja.