Following years of research - and sometimes acrimonious argument - environmental agencies across North America have begun implementing programs of prescribed burning. They are setting low-intensity, controlled fires to change or maintain natural environments. In addition, many fires started by lightning are now allowed to burn in high-altitude wilderness areas where there are few human habitations or timber resources. Such forestry burning is not new; we are just beginning to appreciate the complexities and sophistication of this age-old custom. Anthropologists have noted habitat burning by nearly all known populations of North American Indians. The Indians of Canada's northern boreal forests, or taiga, are among those who until recently employed fire to control and alter selected habitats. In Alberta's remote northern section, Slavey, Beaver, Cree, Chipewyan, and Métis maintained the traditional practices until the completion of the Mackenzie Highway in 1949, when oil field developments brought an end to the region's isolation. With the intrusion of roads and communication systems, environmental agencies were finally able to enforce existing fire laws. Today, just when provincial and national agencies are discovering the advantages of controlled burning, only elders, over sixty can recount their own folk science of fire