An unflattering likeness of a critic? What next?

It's a bit startling to be able to pick up an Iain Pears novel with two fingers. "Massive" and "intricate" tend to be the adjectives that pop up most frequently with regard to the British writer's erudite historical mysteries, the internationally bestselling "An Instance of the Fingerpost" and the acclaimed "The Dream of Scipio."

Both involve weighty theological and philosophical questions, feature detailed re-creations of the past ("Scipio" weaves together lives that span 1,500 years), and clock in at more than 600 pages.

By contrast, "The Portrait" is a stripped-down exercise in creeping dread. It's essentially a 200-page monologue (although much more enjoyable than that description would imply).

The speaker is a Scottish painter, Henry MacAlpine, who is living on a remote island off Brittany during the early 20th century. An eminent art critic and old friend, William Naysmith, has just arrived to have his portrait painted - and to uncover the reason MacAlpine fled London four years before.

As he paints, MacAlpine obliges both Naysmith and the reader, but he has his own motives for taking the commission, and it soon becomes apparent that friendship is not among them.

MacAlpine recounts their years swaggering around Paris and their subsequent success in London - MacAlpine's, as he acknowledges, was due as much to Naysmith's patronage as to his own skill. He reminisces about mutual acquaintances, such as Evelyn, the lone female artist among their set, and the more he talks, the more his repugnance for his friend comes spilling through.

He's clear from the beginning that the portrait isn't likely to be a flattering one, but Naysmith remains, again for reasons quite apart from art or friendship.

We never hear a peep out of Naysmith, and Pears seems to derive a certain amount of glee in completely silencing a critic. Not since Carol O'Connell's "Killing Critics" has a mystery writer had quite this much fun avenging himself. Take lines such as "a critic is to a painter as a eunuch is to a man" and MacAlpine's description of Naysmith's verbal evisceration of a mutual friend:

"Perhaps you began in a spirit of constructive criticism, I don't know. But as you worked your way through each canvas, the joy of the hunt came upon you. The pitilessness of it was terrible ... each painting was dismantled, colour by colour, line by line, form by form. Nothing escaped you: it was a tour de force, a brilliant piece of sustained, improvised destruction. And through it all, poor Anderson had to sit there, politely, respectfully, not able to show on his face how you were torturing him as you ground his dreams to dust."

As fans of his Jonathan Argyll series know, Pears has a background in art history (he's also published nonfiction on the subject), and he spends at least as much time riffing on that topic as he does on the central plot. MacAlpine, for example, has little patience with Post-Impressionists (Cézanne, he acknowledges, has some ability). It's fine if you are French; it's the "faux-français" he can't abide:

"There we were, slopping down great gobs of paint trying to fix something glimpsed for a moment, then half-forgotten.

"As Monet had shown us, so we did. Well and good, it produced a few pretty things....

"By all means, try and capture that brilliant flash of light on the lily pond; the play of autumn sun on the cathedral facade. But we never got much sun in Scotland, you know. Not much light, either."

MacAlpine was never attracted to "prettiness." He's most inspired by the subjects he used to cover as a sketch artist for the newspapers - poverty, murder, suicide, despair - realism at its grimmest.

Now, in quietly ominous words, he tells his subject and us: "It's not finished of course. You miss nothing where painting is concerned. It's unbalanced. The first is a portrait of a man whole in mind and body, and the second shows" ... something we're not giving away.

When planning a murder, at least of the bookish variety, a houseful of suspects is handier than an airtight alibi. Perhaps not a cast of thousands, but at least a baker's dozen of rogues and red herrings to shift the blame around and keep the reader in a state of confusion until the grand unveiling.

Because both the author and the artist are so narrowly focused on their subject, observant readers will have figured out both crime and punishment well before MacAlpine puts his brush down. There's still a great deal of enjoyment to be gained from Pears's wit and able writing, but mystery fans will miss the pleasure of being outsmarted by a master.

• Yvonne Zipp is a freelance writer in Kalamazoo, Mich.