Epsilon is a wolf in Yellowstone National Park. He was born there. When he was only a yearling, Epsilon lost his parents in a fight between rival wolf packs. Epsilon, his brother, and his sister escaped, but they had to survive on their own. They learned how to hunt. They grew up. They formed a strong new pack of wolves, and Epsilon became its leader. Beautifully illustrated, Epsilon is an entertaining and educational story about wolves in Yellowstone National Park.