The indigenous peoples of Australia, the Australian Aborigines, settled the continent more than forty thousand years ago, with some archaeological estimates placing their occupancy at well over fifty thousand years ago. It is most likely that their forebears crossed from Southeast Asia during the Pleistocene period, coming first to the northwest coast and migrating south and east. By the time European explorers and then settlers arrived on Australia's shores in the late eighteenth century, Aboriginal societies, although sharing an economy based on hunting and food gathering, were linguistically and culturally diverse, living across the continent in environments of distinctive ecology and climate. These ranged from inland desert to tropical and temperate coastal zones and alpine regions. Although self-contained for most purposes, neighboring clans gathered for major ceremonies, and localized tribal groupings participated in the trade of goods (such...