Most film critics point to classic conflicts good versus evil, right versus wrong, civilization versus savagery as defining themes of the American Western. In this provocative examination of Westerns from "Tumbleweeds" (1925) to "Rango" (2011), Robin L. Murray and Joseph K. Heumann argue for a more expansive view that moves beyond traditional conflicts to encompass environmental themes and struggles. The environment, after all, is the fundamental stage for most western stories, from land rush dramas that pit sod busters against ranchers to conflicts between mining-town communities and...