The Impossible Dead by Ian Rankin

This is the second novel in the Matthew Fox series; it's Rankin's 25th book. It goes down as smoothly as 25-year-old single malt Scotch.

Inspector Fox is an Edinburgh cop assigned to the Complaints, the cops who investigate other cops. The setup taps into the inevitable tension between the fallible human beings who are trying to bring criminals to justice and the rule of law. As the Romans said, "Quis custodiet ipsos custodes?" As a result, Fox and his two associates are barely tolerated other cops when they are assigned to look into a case of police misconduct.

The Impossible Dead begins as if Fox, Kaye, and Naysmith are on a fairly straightforward investigation to see whether a rogue cop's mates had known what he was up to and tried to protect him. The dialogue is sharp and natural:

"Forrester's the one we should be talking to," Kaye said suddenly, breaking off from his argument with Naysmith.
"Why?"
"Because her first name's Cheryl. My years of experience tells me that makes her a woman."
"And?"
"And if one of her colleagues was a sex pest, surely she'd have had an inkling. Surrounded by blokes circling the wagons when the rumors start flying . . . she's got to know something."

As anyone who has ever read a mystery knows, however, the straightforward investigation morphs into something far more serious and far more complex. It is a sign of Rankin's mastery that he is able to keep the story moving and his large cast of characters from bumping into each other or into the scenery.

He is also a master at giving just enough descriptive detail to convey place, character, and mood. Here is Fox interviewing the elderly widow of a dead politician:

"Fox took another sip of tea and placed the cup and saucer back on the tray. The room was silent for the best part of a minute. He got the feeling that when she was left alone, this was how she sat--calm and still and waiting for death, staring at her reflection in the window, the rest of world lost somewhere beyond. He was reminded of his father [in the elder care facility]: I don't sleep...I just lie here...."

I'm afraid I cannot sum up my feelings better than P.D. James, who is quoted on the book's jacket: "Rankin is a master at what, for me, is one of the important aspects of a crime novel: the integration of setting, plot, characters, and a theme which, for Rankin, is the moral dimension never far from his writing."