Set in Greenbury, N.Y., bestseller Kellerman's plodding 23rd mystery featuring Peter Decker and Rina Lazarus (after 2014's Murder 101) opens with the discovery in a forest of the corpse of college student Eli Wolf, who apparently shot himself. Decker, who now works for the Greenbury PD after recently retiring from the LAPD, investigates. Meanwhile, Tyler McAdams, who left Greenbury PD for Harvard Law School, returns home to study for his exams. Tyler tags along as Decker tries to determine why Eli, who comes from Mennonite stock and was a gifted mathematician, would have committed suicide. When one of Eli's classmates turns out to be a woman who has had a crush on Tyler for years, she can't be ruled out as a suspect in what develops into a murder case. Series fans will be pleased to see that the relationship between Decker and Lazarus, neither of whom has any flaws, remains as affectionate as ever. New readers should be prepared for plenty of schmaltz. (Oct.) © Copyright PWxyz, LLC. All rights reserved.

Detective Peter Decker welcomes his insufferable former colleague Tyler McAdams, shot at the end of Murder 101 (2014), back to the Greenbury, New York, police force with open arms and violent death. McAdams, who's supposed to be studying for his exams at Harvard Law School, says he wants to stay with Decker and his wife, Rina, for peace and quiet and a chance to hit the books without distractions. Distractions promptly arise when Kneed Loft College senior Eli Wolf is found shot to death, his clothes piled neatly next to him, in a snowy field. A car accident six years ago that killed the friend who was driving and broke his brother Jacob's leg scrambled Eli's brain. Born into a Mennonite family whose rapport with each other is laconic even when they're most demonstrative, he's been drifting further into the world of theoretical mathematics and away from everything else. Now that Decker must question Jacob, Eli's closemouthed parents, and his even more socially challenged mentors and friends at Kneed Loft, McAdams is eager to get in on the actionif that's what you want to call the brightly didactic passages explaining Fourier transforms and stochastic oscillators that take the place of Rina Decker's customary disquisitions on Jewish rituals. Fueled by the discovery of some incomprehensible papers Eli hid in his dorm room, Decker and McAdams talk to the boy's sort-of friend Mallon Euler, who turns out to have quite a crush on McAdams; Dr. Theo Rosser, Eli's megalomaniac adviser; and paranoid Dr. Katrina Belfort, who lacks the tenure that would presumably suck her last remaining humanity from her. The discovery of a second corpse sharpens the urgency of their inquiries but does nothing to focus them, until eventually one of their several theories of the case, no more or less interesting than the others, hits home. Move this one to the top of your list if you still pine for linear algebra. The unenlightened may want to wait and see what's on offer next term. Copyright Kirkus Reviews, used with permission.

DR. KAY SCARPETTA, who keeps US coming back to Patricia Cornwell's sprawling crime novels, is one tough broad. As chief medical examiner for the state of Massachusetts, she has no trouble dealing with the gory sights and smells of dead bodies and violent crimes. "A select few of us come into this world not bothered by gruesomeness," she says. "In fact we're drawn to it, fascinated, intrigued." What she can't handle are threats to the person she loves best in the world, her brilliant, prickly niece, Lucy. In DEPRAVED HEART (Morrow/ HarperCollins, $28.99), Scarpetta is on the scene at the "accidental" death of a movie mogul's daughter when she receives a disturbing surveillance video shot in 1997 by Carrie Grethen, Lucy's mentor (and first love) at the F.B.I. Academy in Quantico, Va. Because it suggests that Lucy was in possession of an illegal firearm, Scarpetta worries herself sick that Carrie, a malicious psychopath, will use the clip to undermine her niece's career. But for fuzzy reasons, Scarpetta keeps her worries to herself, unwilling to share them with her husband, an F.B.I. profiler, or her cop friend, Pete Marino. Not even when the F.B.I. comes down on Lucy. Once Scarpetta decides to ferret out Lucy's secrets, the novel becomes more of a psychological thriller than a crime drama, although that suspicious death isn't entirely forgotten. Scarpetta follows the autopsy on her computer screen and even wades into the murky waters of "invisibility technology," hoping to learn how "augmented reality or optical camouflage" might have figured in the case. But the real focus is on Scarpetta's obsession with Carrie: "For years she'd invaded my psyche I waited for her to torture and murder someone- I constantly looked for her when I was with Lucy and when I wasn't. Then I stopped." And then she started again. CHARLES FINCH'S VICTORIAN whodunits, with their resolutely aristocratic sensibility, can be a guilty pleasure for the more plebeian reader. His gentleman sleuth, Charles Lenox, is a partner in a London detective agency, but he's also the brother of a baronet and is married to the daughter of an earl. In HOME BY NIGHTFALL (Minotaur, $25.99), a sterling addition to this well-polished series, all of London is talking about the renowned German pianist who disappeared from his dressing room after a concert. But before Lenox can apply his wits to that locked-room puzzle, he must head to the family estate in Sussex, hoping to console his grief-stricken brother after the sudden death of his wife. A series of odd, mysterious thefts in the nearby town of Markethouse prove the perfect distraction for Sir Edmund Lenox, as well as a chance for Finch to dazzle us with his amusing studies of country folk and his offbeat approach to historical particulars. So while we're treated to all the showy details of an elaborate ball at an ancestral manor, we're also beguiled by tidbits about the importance in Victorian society of wearing a hat and the remarkable contributions of the era's fanatical amateur geologists to the field of natural science. OUTSIDE of a Marvel comic book, can a crime story have too many heroes - even if they're all great guys? Absolutely, and Robert Crais's latest novel, THE PROMISE (Putnam, $27.95), is a case in point. His go-to protagonist, the California private eye Elvis Cole, is first on the job when an executive at a company that manufactures the chemical ingredients for heavy explosives hires him to find its top engineer, a woman who has gone looking for answers after her son was killed in a terrorist bombing. You don't want to fool around with chemical weaponry, international terrorists or a vengeful mother, so Cole recruits his scary friend, Joe Pike, a soldier of fortune who brings along his own scary friend, a "professional warrior" named Jon Stone. These big boys do so much heavy lifting that we almost lose sight of two other heroes, first met in Crais's previous book, the K-9 officer Scott James and his partner, Maggie, a German shepherd with more personality than all of them put together. THE KELLERMANS ARE on the march. In THE THEORY OF DEATH (Morrow/HarperCollins, $26.99), Faye Kellerman writes with her usual sensitivity about troubled teenagers and young adults like Eli Wolf, a math genius whose naked body is found in the woods not far from his college in Greenbury, N.Y. Detective Peter Decker, who relocated to this upstate burg after a more eventful career as a Los Angeles cop, is too conscientious to write off Eli's lonely death as a suicide, but when he opens an investigation it lands him in the snake pit of academic politics. Writing to her strengths, Kellerman shows her customary compassion for isolated souls like Eli and social outliers like his Mennonite farm family. Kellerman's husband, Jonathan, and their son, Jesse, team up in THE GOLEM OF PARIS (Putnam, $27.95) on something truly off the wall - a classically constructed detective story featuring the tormented hero of a previous book ("The Golem of Hollywood") that morphs into a supernatural thriller combining elements of Jewish legend, religious mysticism and pagan mythology. While the novel's paranormal elements don't mesh easily with the procedural work, it's hard to resist a protagonist who does battle with demonic giants and is in thrall to a woman who's part angel and part bug.

Former L.A. detective Peter Decker is living and working as police chief in Greenbury, a small town in upstate New York, where a college student, Eli Wolf, is found dead in the forest, an apparent suicide. Decker investigates with the help of visiting Harvard law student Tyler McAdams (introduced in Murder 101, 2014), who is staying with Peter and his wife, Rina Lazarus, ostensibly to study for his final exams without distraction, but the distractions mount as the investigation continues. Wolf was Mennonite and estranged from his father. He'd been in a bad car accident several years earlier, resulting in a form of brain damage that left him obsessed with math. Wolf's one social connection was to another math student, who had a crush on him since they were teenagers, but that doesn't leave her out as suspect. Fans of Kellerman's long-running series may find that this installment has too much math and not enough Rina, slowing down the story considerably. Still, it's a necessary purchase for libraries collecting the full series, and, of course, it's a natural for math-loving mystery readers.--Alesi, Stacy Copyright 2015 Booklist