How do you manage John Rebus and Harry Bosch as they face up to their twilight years?

Ian Rankin: In A House Of Lies

Michael Connelly: Dark Sacred Night

Two stalwarts of the crime writing genre, and both with definitive characters now approaching their senior years.

And that hands both of them a real challenge.

How do you manage John Rebus and Harry Bosch as they face up to their twilight years outwith the force?

Kill them off with an explosive final outing?

Allow them to go quietly into the night?

Or let old age, and failing health, take its natural course.

Rebus and Bosch are both growing old in real time - something not old crime detectives do - and that gives them a finite shelf life.

Both have endured across several decades and multiple novels, both are now facing the end game.

They’re not quite there yet, but then “when” and “how” are standing on the horizon.

In Bosch, Connelly has created one of the finest fictional  detectives. His story, and career, span 21 novels across 27 years all of which which are laser-sharp, outstanding reads.

He comes with a complex and compelling back story - the son of a prostitute, a former Vietnam vet who worked the tunnels dug by the Vietcong - and an equally fragmented personal life.

But he is also getting old.

His LAPD service is done and dusted, but he hovers on the fringes, working as a PI and somehow

ending up immersed in live cases with old partners and names and faces with connections to his past.

With his health less than perfect, the desire to bring justice to the grieving remains strong, and Dark Sacred Night taps into a previous storyline from The Two Kinds Of Truth which sees him take in mother addicted to drugs while pledging to find the killers of her daughter Daisy.

Connelly keeps Bosch very much at the heart of the case, while also investigating a cold case gang killing, and he pulls all the strands together with his customary forensic style.

But Bosch is surely facing limited time.

It will be fascinating seeing how Connelly handles his character’s twilight years. I suspect there are still a few twists to come yet.

And the same goes for Ian Rankin who has created a true legend in John Rebus.

Like Bosch, he too is out of the force, but incapable of moving quietly on the sidelines to enjoy his album collection and watch the world go by.

Like Connelly, Rankin immerses him in an investigation into the death of a private investigator whose body is found many years after he disappeared.

It’s classic Rankin - old characters return, plots are twisted, and lives collide - but what really fascinates is the gradual disintegration of Rebus’ health following a diagnosis of COPD.

The book gave a clear sense of the sands of time trickling away as he struggled to draw breath.

Possibly for the first time, Rebus felt like an old man, his health gradually crumbling, and grudgingly realising his doctor’s advice may have to be followed.

So, where next? His nemesis, Cafferty, is also growing old - do they both go out in a blaze of glory, or find mutual peace in their final years? The bonds that tie them together are an integral part of In A House Of Lies.

You’re left with a sense that fading health may do for Rebus, but, at the same time, he still has that burning desire to sole crimes, deliver justice and, who knows, maybe finally oust Cafferty from his retirement penthouse apartment into a spartan cell.