The wolves and moose of Isle Royale National Park, an island (544 km 2 ) in Lake Superior (North America), have been under study since 1959, in the longest predator-prey study of such intensity in the world. Isle Royale's biogeography (remote island) and management (no hunting or trapping of wildlife, no forest management) are important unique features. During its 45-year history, this research has contributed valuable insights to fundamental aspects of population ecology. In the next five years the dynamics and interactions of wolves, moose, and vegetation will continue to be the primary focus for research, with the following three emphases: ecological relationships between trophic levels in this rather simple ecosystem, significance of inbreeding depression among wolves in this small, isolated population, and effects of wolf and moose parasites on their dynamic equilibrium. Gray wolves and humans have competed over domestic and wild prey from the dawn of humanity to the present, which led to overzealous but successful campaigns throughout the Northern Hemisphere to eliminate this important carnivore. After reaching a historic low point in the 1950s, the gray wolf has expanded through natural recovery and introduction programs by the U.S. government such that it will soon be removed from the list of federally-protected Endangered Species. Wolf recovery will significantly affect human economies as well as ecosystems that have been wolf-free for decades, even centuries. Long-term research on this species and its prey at Isle Royale has contributed to expanded knowledge of wolf behavior and ecology, with a large impact on public opinion. Isle Royale provides a key site, indeed the only site, where the ecological role of the wolf in an entire ecosystem can unfold without significant human influence, thereby providing a useful baseline of natural ecological dynamics.