It’s a risk to make a book editor the main character of your own book. When I picked up Judith Flanders’ A MURDER OF MAGPIES, I couldn’t help wondering what her own editor thought of this portrait of Sam (short for Samantha) Fair, the acerbic 40-year-old know-it-all employed by the fictional London publisher Timmins & Ross. Sam’s wry, self-deprecating, suffer-no-fools voice dominates the novel, Flanders’ first venture into detective fiction.

The Unlikely Sleuth is a staple of thrillers, and Sam, a self-described “middle-aged, middling-ly successful editor,” is continually shocked to find herself caught up in murder and mayhem. After all, she isn’t a star like her mother, Helena, a partner in a London law firm who is frighteningly brilliant, brisk and efficient --- and apparently able to do without sleep.  Sam, in contrast, prefers caffeine to exercise (she runs, but claims it’s more of “an exhausted stagger”), books to TV (she doesn’t even own one) and unglamorous invisibility to celebrity.

And yet, as Sam lurches from one unsavory happenstance to another (burgled, mugged, tailed, drugged), she turns out to have Helena’s genes after all. She cows VIPs, pulling out a book when they keep her waiting, thus undercutting the power play (“[T]here is no fun in ignoring someone who is happy to be ignored”). She faces down villains, commits burglaries (in a good cause) and charms policemen. One in particular.

The story begins with a visit from a CID inspector by the name of Jacob (Jake) Field, whom I spotted as the Love Interest (not difficult) from the get-go. He is investigating a hit-and-run that left a bike courier dead; said courier was delivering a manuscript to Sam from one of her favorite authors, fashion journalist Kit Lovell. Flamboyant, clever and “the best gossip on the planet,” Kit writes “quick-and-dirty low-downs on the rich and famous” that race off the racks like Uniqlo cashmere. His new book is about Rodrigo Alemán, a Spanish designer who met a violent death, and it will need to be vetted for libel, but Sam doesn’t expect a hold-up in publication. “This isn’t trouble,” she says to her anxious editor-in-chief. “It just needs a legal read.”

"Sam and Jake’s budding relationship is subtle and appealing, reminiscent of Lord Peter Wimsey and Harriet Vane in Dorothy Sayers’ peerless mysteries, or maybe Tracy and Hepburn’s cinematic sparring."

She is so wrong. Soon enough, there is nothing but trouble: Kit has vanished and is feared dead, while Sam, with the help of Jake and Helena --- and a mysterious upstairs neighbor, Pavel Rudiger, who turns out to be a celebrated Czech architect --- has to survive all sorts of jeopardy in her hunt for the truth. Finally, she arrives at a solution not only to the messenger’s death, but to Alemán’s murder and Kit’s disappearance. There’s no way I would divulge the identity of the culprits, but Flanders gives the denouement a surprising feminist twist.

The setting is terrific, too. Either Flanders once worked in publishing herself or she grilled her editors pretty intensely, for her scenes at Timmins & Ross are spot on. A former editor myself, I recognized all of Sam’s gripes: being accosted by would-be authors, manuscripts in hand; dealing with lame marketing materials; attending editorial meetings too deadly for words; and enduring missed deadlines (“Most authors,” says Sam, “think that if they’ve delivered a manuscript within their lifetime it meets the legal definition of ‘on schedule’”).

There are a few captivating subplots, one featuring Sam’s bestselling author of mature, comfortable “women’s reads,” Breda McManus (possibly based on the late, lamented Irish author Maeve Binchy), who has unaccountably turned in an appalling chick-lit novel, Toujours Twenty-One. How that turns out is a kick in the face to pretentiously literary editors and writers, as is the portrait of a 26-year-old colleague, straight from Oxford, who uses words like mega and ultimately gets his comeuppance in a satisfying confrontation with Sam.

Flanders also includes a number of droll set pieces: an opening at the Tate Modern that skewers museum snobs; a dinner at the ultra-stuffy and misogynistic Reform Club (the ladies’ bathroom is located up the back stairs, “which is where the Club has decided women are to be hidden away to do whatever it is women do”); and a luncheon composed entirely of healthful foods like lentil soufflé, which “looked like the stuff you scrape off the bottom of your shoe.”

But these are more satirical than suspenseful, and that’s the problem: Much of what is most diverting in A MURDER OF MAGPIES has nothing to do with the mystery itself. Flanders is hardly a novice writer (she’s produced five books of Victorian biography and social history, including one called THE INVENTION OF MURDER: How the Victorians Revelled in Death and Detection), but she is new to this genre, and I’m afraid it shows.

First, there is the plausibility issue: How likely is it that a CID inspector (Jake) would just happen to stumble over a high-powered legal mind (Helena) and accept her as his partner in crime-solving? Then there is the question of momentum. The novel sags each time it launches into lengthy discussions of money laundering and IT departments and shell companies and false invoicing and arms trading. Flanders’ characters are forever thinking aloud, and whenever one of them starts summarizing What We Know So Far, my interest flagged. There just isn’t enough mystery in this mystery.

Yet there is so much to like in A MURDER OF MAGPIES that you should read it anyway, maybe more as a witty love story than a thriller. Sam and Jake’s budding relationship is subtle and appealing, reminiscent of Lord Peter Wimsey and Harriet Vane in Dorothy Sayers’ peerless mysteries, or maybe Tracy and Hepburn’s cinematic sparring.

Consider the scene in which Sam says to Jake, after a discussion in which he proves to know more about her personal life than she had suspected, “I’m getting less and less sure about the benefits of being with someone who makes deductions for a living.” Jake retorts: “Look on the bright side. With most men, you can be in a white rage with them for days, and they don’t even notice.”

Maybe it’s not a great mystery, but it’s a fine romance.