Books with title Anonymouse: A Story about Pen Pals

Parsnip Peppersnatch is an unassuming mouse who resides in P.O. Box 12. Every night he scavenges for food, but he's always careful to get home before the people come! If there's one thing Parsnip simply cannot bear, it's people! Eek! But one day, Parsnip sees a small person who looks very sad. Suddenly he finds himself involved in a scheme that will take courage, know-how and even a few anonymous letters!