No animal is more symbolic of the Arctic than the Polar Bear. In the short space of 150,000 years, it has undergone behavioural and physiological changes to evolve from a Grizzly Bear into the most specialised predator of the Arctic sea ice. Yet, its survival is now threatened by global warming. Renowned Polar Bear scientist Ian Stirling compresses 40 years of research on these iconic mammals into a new and comprehensive natural history. In accessible language he explains their evolution, life history, behaviour, how they are researched, and the current threat to their very existence. He also explains why the Polar Bears of Hudson Bay have become so important to our understanding of the species, and how Churchill became the Polar Bear Capital of the World. Maps, tables, graphs and the most diverse collection of Polar Bear photographs ever assembled in a single book provide greater insight into this unique mammal. Underlying it all is a call for immediate action, which can still save this magnificent hunter of the Arctic.