The Capital-based writer – whose next book The Dark Remains sees him revive the late William McIlvanney's sleuth Jack Laidlaw – has said in the past that, because Rebus ages in real time, the series has a shelf-life.
The now-retired Edinburgh cop turned private detective (of sorts) will be knocking on 70 in the next instalment.
Now 60 himself, Rankin admitted recently that finding a way to end the series is “always at the back of my mind”.
“Now he is retired, he is old, he’s got health problems, he can’t climb stairs,” he said.
“There is only so much I can do with him now. He’s got inbuilt decrepitude so I don’t know how many more books I can realistically write.”
Now, in a new interview, with The Bookseller magazine, Rankin opened the door for another writer to continue the Inspector Rebus series after his death – but he also hinted there could be new life in the character from his own pen.
Asked if he would mind another writer taking on the Rebus series after his own death, Rankin said: “Well, I guess I wouldn’t be bothered that much because I wouldn’t be around to have any say.
“Maybe it’s inevitable, as these days if you have a good saleable character or a brand, they can live long past the death of their creator.
“I’ve always thought maybe someone could come along and do a young Rebus, like young Morse in ‘Endeavour’.
“I’ve thought about doing it myself, but that would be Rebus in the 1970s and ’80s, which means a historical novel, and I used to think that would be too much work.
“But maybe [The Dark Remains] has whetted my appetite for doing a young Rebus.”
Rankin also told The Bookseller he can only see one more Rebus book – but as he admits, he's said that before.
“I’ve enjoyed the ageing process,” he said. “He’s not the same guy as I was writing about five years ago, so that makes it fresh, keeps me on my toes.
“I always say it and I’m going to say it again, I can only see one more Rebus book.
“I can never see further ahead than one book and I might have said it was the last Rebus seven or eight times in the past.
“But every time I’ve said that something has come along that has suggested itself as a theme or a story where he is the ideal character. So it seems he always has that wee bit of life left and he just refuses to leave the building.”
Last year, Rankin revealed how much he earns from his Rebus novels today – and what he was paid for his first book.
In an interview with the Daily Mail, the author said he was paid just £500 for his first book, The Flood, in 1986.
These days, however, he is earning significantly more.
A Song For The Dark Times is Rankin’s 24th and most recent Inspector Rebus novel, and he said books featuring his most famous literary creation now “make me a seven-figure sum”.