A very demure detective

Crime: Edinburgh through Alexander McCall Smith's eyes is a genteel and very proper place, or at least that's the experience of the characters in his new novel.

They go to the Usher Hall for concerts, live in well-appointed period homes, have private incomes or work in sober law offices or investment banking. In the middle of this is Isabel Dalhousie, amateur sleuth in the Miss Marple tradition, or, for TV watchers, a version of Jessica Fletcher from Murder She Wrote.

For a detective novel, the plot is straightforward and on the slim side without any of the twists and turns that make this genre truly satisfying.

At a concert one night, Isabel is just leaving her seat when, before her eyes, a young man plunges from the upper circle down to his death. She is guided by a strong ethical and moral compass and feels that because she witnessed the man's death and suspects murder, she is obliged to find out what really happened. Throughout the novel, she is helped by the small cast of characters in her tidy life, including Grace, her straight-talking housekeeper, Cat, her beautiful niece who runs a delicatessen, and Cat's ex-boyfriend, Jamie, an old-fogey type musician.

The name of the novel comes from a club that Isabel, an editor of the Review of Applied Ethics, hopes to find the time to form. Interwoven with her sleuthing is the satisfying added dimension of her ladylike wrestling with philosophical questions, such as is it ever right to tell a lie or how responsible are we for our mental state.

McCall Smith's best-known book, The No 1 Ladies' Detective Agency, is something of a publishing phenomenon. The Edinburgh-based 56-year-old professor of medical law has always been a prolific writer, but he struck commercial paydirt with his lady detectives. It was first published in 1988 and sales trickled for a decade until it became a word-of-mouth, book-club fuelled, runaway success, selling more than 1.5 million copies.

There's probably no gender breakdown of McCall Smith's usual readers but it's safe to assume they are overwhelmingly female and the same will go for this new book, although for this female reader at least, there is much about Isabel's character that jars. The phenomenon of middle youth has completely passed her by, she's skipped straight though to the outer reaches of middle age.

Only in her very early 40s (that's younger than Madonna, by the way), she's a twin-set and pearls sort of woman, her housekeeper makes her lunch, she takes naps in the afternoon and talks to her 20- something niece as if she was adrift from her by at least two generations. Half-way through, I got the creeping suspicion that McCall Smith had originally intended Isabel to be a far older woman and had written her as such, and only changed her date of birth at the 11th hour.

This is the sort of detective book where you're not going to be troubled by forensic detail, blood and guts and small firearms, but the writing is so strong and tight that even if you can't bring yourself to care too much what happened to the young man who tumbled over the balcony, the pages turn effortlessly.

Indeed, the plot doesn't really survive intense scrutiny; there are too many far-fetched connections, which will madden hardcore detective readers who like watertight detail.

The Sunday Philosophy Club By Alexander McCall Smith, Little Brown, 281pp. £14.99

Bernice Harrison is a journalist and Radio Critic of The Irish Times