True Grit by Charles Portis. The movie with John Wayne was a faithful adaptation, although Wikipedia lists the differences, if you’re curious. Oh, and the Coen brothers are doing a remake, with Jeff Bridges as Rooster Cogburn and Matt Damon as LaBouef (the Glenn Campbell role). Newcomer Hailee Steinfeld plays Mattie Ross (the Kim Darby role). Hard to see how they could improve or even rival the John Wayne version, but I suspect the Coen brothers might make a fair show of it.
You writers: take a look at True Grit (the novel) if you get the chance. Masterful characterization.
D.