Frog and the Stranger (Max Velthuijs) Paperback / softback

 When Rat comes to live at the edge of their wood, the animals decide  they don't like having a stranger in their midst. But Frog is friendly  by nature, and decides to find out if Rat is really as unpleasant as he  is made out to be. As Frog discovers, Rat is intelligent and good  hearted, and proves in a series of unexpected emergencies that the other  animals have been too quick to condemn him.