I remember seeing The Searchers as part of a Western film exhibit at the East Wing of the National Gallery many years ago. This trailer greatly simplifies the theme of the movie, as it is perhaps the greatest Western film ever made, not just because of its stunning cinematography but the sense of cultural ambiguity John Ford creates in his big screen adaptation of Alan Le May's novel from a few years before.
As J. Hoberman points out in his review for the New York Times, Le May's story was based on an 1836 account of a 9-year-old girl, Cynthia Ann Parker, who was abducted by Comanches in an ongoing range war with Texas settlers. Young Cynthia was forced to watch her parents killed, and was subsequently raised in the Comanche tribe, as personified by "Scar" in the movie. It was one of John Wayne's few enigmatic roles, a former Southern Civil War soldier bent on revenge for the deaths of his cousins, and seeming to have no sympathy for the grown-up girl, now known by her Comanche name.
Glenn Frankel has sought out the history of the film, not just in its making but in the story of Cynthia Ann Parker, the range wars taking place in the West, and the genre of Western writing that had grown up in the 1830s, most notably in the writings of John Fenimore Cooper, in which abductions figured heavily into his novels.
Sounds like a great read.