This non-fiction book is about a great mountain wilderness where wolves and their prey continue to live in a delicate, natural balance. Using a combination of narrative non-fiction and easy-to-follow essays, this book explores the natural history of the Yukon during the last 20,000 years. Part 1 - History - chronicles wolf evolution since the end of the ice age, including the great collapse of Beringia large mammals and the domination by caribou through the Holocene. Other chapters include the relation between ancient native people and wolves, and the importance of Jack London's Yukon stories to our collective image of wolves as a symbol of wilderness. Other history chapters explore the relentless, but largely ineffective attempts to reduce wolves through bounties, poison and hunting through the 20th century. Part 2 - Understanding - describes the author's original research into wolf relations to moose, caribou, Dall's sheep, ravens, and grizzly bears. In the last chapter Hayes, who studied three Yukon wolf control projects, explains why broad-scale killing of wolves has only produced brief benefits for moose and caribou, and why the practice should end. Finally, the book raises questions about how we should use and conserve one of the largest remaining tracts of complete wilderness on the continent.