Mary Anne and the Library Mystery — Ann M. Martin

America's favorite baby-sitters are detectives, too!

The Stoneybrook Library children's room is holding a Readathon to raise money for new books. And Mary Anne, who loves to read, is helping out by finding good books for the kids to read.

But things at the library get really scary when small fires break out. The police know the fires have been set. But by whom? And why would someone want to burn down Stoneybrook's library -- especially when there are tons of kids around for the Readathon?

This is one serious mystery that Mary Anne's not going to let go unsolved!