Review: Saints Of The Shadow Bible by Ian Rankin The evidence isn't conclusive, but novel No 20 could be the last for Rankin's ageing detective Saints Of The Shadow Bible Ian Rankin Orion Books, £18.99 "REBUS - saint or sinner?" asks the tagline on the cover of Ian Rankin's 20th novel about his thrawn Edinburgh detective, but those who have read even one of the other 19 already know that the rather boring answer is: quite a bit of both. He's no saint, certainly. "You going to slam me into a wall, knock me out cold again?" asks the first wrong'un he interrogates within the novel's opening three pages. But as this interrogation - and an altogether more explosive one in its last three pages - both take place beneath Arthur's Seat, the plot's Hogg wash prompts a slightly different question. Is Rebus any kind of justified sinner? The novel is set against the background of the referendum campaign, although the only direct political debate to surface is a single sentence when Rebus catches a radio discussion on whether an independent Scotland could remain part of Nato if it gave up nuclear weapons. After a couple of minutes, Rebus could feel his blood pressure rising. He reached for a CD and slid it home. Spooky Tooth's second album. "Better," he said to himself." Twenty novels in, Rankin's readers all know that this is exactly what Rebus would do. Politics isn't his passion. Solving crimes - even ones that would be easier to sidestep - is. It's also a reminder of just how ancient Rebus is these days: Spooky Tooth's second album, the music of his youth, dates from 1968. Back in the present, with re-markable even-handedness, crime is threatening to destabilise both sides in the referendum campaign. The Yes campaign has to cope with the apparent murder of the SNP Justice Minister following a housebreaking. But it's the possible involvement in another murder by Stefan Gilmour, prominent businessman and leading figure in the No campaign, that threatens to take Rebus off the force for good. Back in the 1980s, Gilmour had been the detective inspector at Summerhall police station when John Rebus was a lowly DC. These were the Life On Mars days of crime-busting, when the strict letter of the law was regularly bent out of shape, with fists flying in the interrogation rooms, evidence routinely planted, and blind eyes turned to whatever snitches got up to - even, in the case of Gilmour's snitch, Saunders, as far as murder. The Summerhall team called themselves the Saints of the Shadow Bible - the shadow bible in question being the book of Scots law on which they swore to cover up their collective rule-bending in the name of the greater good. Rebus took the vow too, but because he was a novice, he wasn't really trusted. Hence the double ambiguity: was Rebus truly a saint, and a loyal member of the Summerhall team? Because if he was, he'd really be a sinner. All of this is neatly sprung open by the Scottish Government's decision (as happened in 2011) to allow exemptions to the double jeopardy rule which would allow acquitted suspects to be tried again in the event of any new evidence emerging. Rankin cannily uses this to have his fictional Scottish Solicitor-General reopen the case of Gilmour's snitch. She calls on Malcolm Fox - Rankin's other main protagonist - to investigate. And so begins the case that many of Rankin's fans have been anticipating ever since he introduced Fox as a straight-arrow, if bland, foil to the maverick Rebus. In Standing In Another Man's Grave, the two men came up against each only tangentially: the unanswered need remained to see what happened when they worked together, each with a different methodology and suspicious of the other. Precisely how it all pans out is beyond the remit of this review, although there's a satisfyingly detailed complexity about the police procedural plotting that few crime writers could hope to match. On top of that, mention of Rebus's past affair with the wife of one of his former colleagues (now seriously ill) pushes him still further into the shadowlands of moral ambiguity, which is where he best belongs. I can't say that I'm always convinced by Rebus's hard-bitten dialogue ("Can I toss another tiny grenade into your foxhole?"), and the density of plot in the final chapters takes a bit of following and involves some hefty coincidences. If you've not read a Rebus novel before, you wouldn't want to start here. In fact, what with 20 being a nice round number, with Rankin reportedly out of contract with Orion for the first time since 1987 and taking a year off writing, and with Rebus feeling his age and getting bested in physical fights with villains, I wonder how much more we'll see of Edinburgh's most famous detective. I hope I've got those clues wrong, but even if I haven't, at least here Rebus gets an exit scene that lingers in the mind long after the final sentence. Twitter: @scotsmandavid