I got curious about this because so many people online keep asking whether 'Goodbye, my mate' sprang from a blockbuster book, and the short, confident truth I’ve come to rely on is: no, it wasn’t adapted from a bestselling novel. When I dug into the credits and interviews around the release, the creators consistently credited a screenplay and original story development rather than citing a pre-existing title. That’s usually the clearest clue — you’ll see "screenplay by" and not "based on the novel by" in official materials.
What’s interesting to me is how often films that feel novel-like in tone get assumed to have literary origins. 'Goodbye, my mate' has that layered character work and melancholic pacing that reminds me of quieter contemporary novels, so fans naturally start hunting for a source. There has been talk of small tie-in novellas and a later novelization for readers who wanted more background, but those tie-ins didn’t chart as bestsellers and came after the film’s release, which points to the movie being the primary creation.
I kind of love that it began as an original screenplay — it shows the writers allowed the story to breathe specifically for the screen instead of shoehorning prose into a visual medium. I’m still fond of digging through scripts and novelizations, but in this case I prefer the movie’s version; it hits differently knowing it wasn’t lifted from a famous book.