Edinburgh police inspector John Rebus's obsession--rock & roll--seems odd for a man whose dark, depressed side is so central to his character, but Ian Rankin always manages to work it gracefully into his noirish novels featuring Rebus. In Set in Darkness, Rebus has a fling with Lorna Grieve, a faded rock muse who's the sister of Roddy Grieve, an up-and-coming politico who turns up dead on the grounds of the boarded-up hospital that's being torn down to make way for the new Scottish Parliament. Grieve's body is the second in the space of days found at Queensberry House; the first was a skeleton bricked up in the fireplace. That decades-old murder seems to be tied to the suicide of a mysterious homeless man whose hefty bank balance is revealed well before his true identity. 'So what's the story with Mr Supertramp anyway?' 'He had all this money he either couldn't spend or didn't want to. He took on a new identity. My theory is that he was hiding.' 'Maybe.' He was rifling through the scraps on the desk. She folded her arms, gave him a hard look which he failed to notice. He opened the bread bag and shook out the contents: disposable razor, a sliver of soap, toothbrush. 'An organized mind,' he said. 'Makes himself a wash bag. Doesn't like being dirty.' 'It's like he was acting the part,' she said. There are always plenty of subplots in a Rankin mystery. This time he adds a stalker who happens to be one of Rebus's colleagues, a cou