When opossums' habitats are threatened and they move into urban areas, they pose a high risk of disease transmission to humans. This has given them a bad reputation. However, left alone in the forest, opossums make up a vital part of the ecosystem. One way they help humans is by eating large amounts of ticks, which limits the spread of Lyme disease and other sicknesses. Full-color photographs and a detailed graphic organizer give readers more information about the role of opossums in nature. A glossary of new terms is included to foster a deeper understanding of the material.