I was just looking into this the other day! The main adaptation of 'The Devil's Own' is, of course, the 1997 film starring Brad Pitt and Harrison Ford. It's a bit of a loose adaptation, though—changes quite a bit from the book, especially making Brad Pitt's character more of a central, sympathetic figure. The book feels grittier, more rooted in the complexities of the Northern Irish conflict, while the movie leans into the buddy-cop-on-the-run vibe. It's entertaining, but you have to separate them in your mind.
There was also talk of a TV miniseries years back that never materialized. Honestly, I think the book's structure would work better for a limited series now, something that could really dig into the moral ambiguity and historical weight. The film adaptation's fun for a night in, but it doesn't capture the novel's full depth for me. I still watch it occasionally for the performances, but with the caveat that it's a very Hollywood take on the material.