Little Mouse loves mint tea and lemon cookies and enjoys reading encyclopedias. One day, the roots of a plant pierce the ceiling of her burrow. Amazed, she realizes that she doesn't know much about the nature around her?but it gives her an idea. She decides to write her own encyclopedia! The reader follows Little Mouse as she explores, questions, and experiments her way into the worlds of insects, trees, birds, and amphibians, both on land and in water, to discover many ecological processes and phenomena.