Open Range is a 2003 American revisionist Western film directed and co-produced by Kevin Costner, written by Craig Storper and based on the novel The Open Range Men by Lauran Paine. It stars Robert Duvall and Costner, with Annette Bening, Michael Gambon, and Michael Jeter appearing in supporting roles. It presents a range war that happens when free-grazing herder "Boss" Spearman (Duvall) and his cowboys enter the Montana territory of cattle baron Denton Baxter (Gambon).