"Proulx's story summarizes large portions of the lives and
relationships of Jack and Ennis, leaving much to the reader's imagination. In the screenplay, many of these incidents are spelled out in more detail. The men's marriages and
relationships with their wives and wives' families, Jack's sojourns to Mexico, and other ele
ments of their lives when they're not together are given more attention in the movie. Still, the screenplay stays on track with the story as Proulx presents it. Some details are extrapolated or added, but for the most part the screenplay expansion grows organically from the source material. Because Proulx leaves a clear road map for her characters, McMurtry and Ossana were able to fill in the details along that throughline, and did a compelling job of it."