This is a scientific monograph based upon 150 radio-collared wolves and their associated packs. The publication includes chapters on morphology, demography, distribution and movements, predator-prey relationships, habitat relationships, and off-territory spacing, the later being the most detailed analysis of migratory wolf behaviour. The hypothesis is rejected that the population is sustainable, and consequently the study led to a permanent ban on wolf killing around the park, the first North America park to provide this additional level of protection for its large carnivore population.