Book excerpt: In Common and Contested Ground, Theodore Binnema provides a sweeping and innovative interpretation of the history of the northwestern plains and its peoples from prehistoric times to the Lewis and Clark Expedition. The real history of the northwestern plains between a.d. 200 and 1806 was far more complex, nuanced, and paradoxical than often imagined. Drawn by vast herds of buffalo and abundant resources, Native peoples, fur traders, and settlers moved across the region establishing intricate patterns of trade, diplomacy, and warfare. In the process, the northwestern plains became a common and contested ground. Drawing on a wide range of sources, Binnema examines the impact of technology on the peoples of the plains, beginning with the bow and arrow and continuing through the arrival of the horse, European weapons, Old World diseases, and Euroamerican traders. His focus on the environment and its effect on patterns of behaviour and settlement brings a unique perspective to the history of the region.