DALLAS MURPHY'S debut mystery, Lover Man (Scribner's, $14.95), is a bouncy, quirky, funny mystery with racy dialogue, hip New York scene, and a hero who is almost as endearing as his mutt.

The mutt is named Jellyroll, the R-r-ruff Dog on TV dog food commercials, who supports his master in grand style. Artie Deemer is the laid-back narrator-hero, for whom happiness is listening to jazz greats as he watches tugboats on the Hudson. The storyline makes more twists and turns than a New York cabdriver running up the meter -- the long arm of the past, switched identities, photo negatives stashed in a refrigerator tray, drug trafficking, the Mob, blackmail, a Ross Macdonald casebook of Freudian motivations. Finally, throw in a host of character cameos from a hippie lawyer to a Caribbean bodyguard named Calabash.

With all that, it would seem that you couldn't miss. And Murphy doesn't miss in Lover Man. An overambitious scenario is the only thing that mars what might have been an absolutely smashing debut.

Near the end, Artie observes: "This was growing Byzantine. I tried to untangle the implications." So will the reader -- after being left breathless by the solid jolt of the climax.

Artie Deemer is listening to a John Coltrane record of "These Are My Favorite Things" when two cops come to tell him that his former lover, Billie Burke, a photographer, has been found drowned in her bathtub.

Later Billie's one-time lesbian lover delivers a cryptic posthumous message from Billie to Artie. The note directs him to check the ice tray in her refrigerator. He does and finds some negatives -- and also a corpse.

It's a strange collection of negatives taken of other photos, which don't seem to have much in common. There are old photos from a family album, a Life magazine cover from 1944 showing a dashing fighter pilot, and recent snaps of an antique store across the street from Billie's studio.

Several other people also want the negatives very badly, and this leads to trouble for Artie. When Artie receives a bill from the Bright Bay Nursing Home, he finds Billie's mother and learns that Billie's father was a World War II ace who crashed in a fiery test flight after the war.

Revelation follows revelation at a bewildering and breakneck pace. It all leads to a mid-air confrontation over the Bahamas in a World War II Martin B-26 Marauder bomber.

In Lover Man, the New York scene comes alive, from a snooker & billiard academy to the morgue. Author Murphy, a playwright, has an ear for street talk and an eye for telling detail.

There are some hilarious moments and also some touching ones. One of the funniest scenes comes when Jellyroll is rehearsing a TV commercial and quickly senses that the actor portraying his doting master really hates dogs and would rather kick him than pat him on the head.

After hearing of Billie's death, Artie puts a jazz record on the stereo player and remembers the good old days with Jellyroll and Billie when ". . . someone would sing 'Lover Man,' Lady Day or Ella, and we'd have before us a lifetime of sunny summer mornings."

Sperm Wails

IT'S A very unusual case that takes Jake Samson and his sidekick, Rosie, to the town of Wheeler, on the cold, windy, wet northern California coast one January. Someone has filched the frozen assets of the North Coast Sperm Bank and dumped thousands of vials of donated sperm into the ocean.

In Shelley Singer's Spit in the Ocean (St. Martin's, $14.95), Jake learns about cryopreservation of sperm in liquid nitrogen and how sperm banks operate for both male donors (they may be working on jobs with radioactive exposure, starting cancer therapy, providing a backup before vasectomies, or doing it for money) and for women (they may have infertile partners or want to have a child by an anonymous donor with no paternal rights).

When the police treat the sperm bank theft as a youthful prank rather than a serious crime, the owner hires Jake, an unlicensed private investigator whose friends keep turning up jobs for him. Spit in the Ocean is his fourth outing.

Jake is one of the nicer guys in the private-eye business. He operates in a relaxed, casual style without need for macho posturing. When Rosie joshes him about being a tough guy, Jake answers: "Never said I was. Never will say so. People start expecting tough, a guy could get hurt."

As Jake and Rosie (she's his tenant back in the San Francisco Bay Area and keeps an eye out for lesbian alliances) are investigating the theft, one of the bank's clerks dies in a fall over a cliff. Jake and Rosie prove her fall was no accident and the break-in at the sperm bank was no prank.

Armor and the Man

THERE ARE Civil War buffs, who dress up in blue and gray uniforms and reenact battles and gather around campfires to sing old songs. Then there are medieval buffs, who join the Society for Creative Anachronism and try to recreate the Middle Ages -- without the fleas, dirt and intolerance -- by dressing medievally and behaving chivalrously.

Each year thousands of SCA members gather at a campground in Pennsylvania to stage a war in full period costume with 60-pound armor suits and polearms. That's the distinctive setting for Murder at the War (St. Martin's, $16.95), which is Mary Monica Pulver's first mystery novel.

"I was just thinking that the Society for Creative Anachronism is actually very like the old Norse myth of Valhalla: You can fight all day, get killed any number of times, and still be in great shape for the feast that night," one of the SCA members points out on the way to join in the medieval war game.

But that unfortunately doesn't hold true for Lord Thorstane Shieldbreaker, who in the "mundane" world was Randy Unwin, a hospital orderly and delivery-truck driver in Cleveland. Thorstane is found mortally wounded, stabbed by an ice pick, on the make-believe battlefield. As both Thorstane and Randy, he was a mean drunk with a vicious tongue.

Unfortunately, Thorstane's murder doesn't occur until the midpoint of Murder at the War. Until then, Pulver, who is a most enthusiastic member of the Society for Creative Anachronism, spends the first half of the book in conversations and actions designed to explain the Society's attractions and its quest for authenticity in garb, speech and battle games. It's interesting -- but only up to a point. And it does nothing to further the cause of the plot.

As it turns out, there isn't that much of a puzzle when it comes to solving the murder. The fun comes in the clash of cultures, not only between 20th-century policemen and Middle Ages buffs but also among the Society's members themselves, who switch back and forth from their medieval personae to their everyday identities in the contemporary "mundane" world.

Love and Death in Norway

WHAT AN inviting target for Robert Barnard's satirical shafts -- an international convention of romance writers. The Cherry Blossom Corpse (Scribner's, $14.95) does not turn up in Washington. The corpse -- that of a best-selling writer of romances -- surfaces in Norway, where cherry trees also bloom. The body of the flamboyant Amanda Fairchild is found floating in a lake, bearing a bough of a blossoming cherry tree. It is an inspired, romantic touch by the murderer, drawing on one of Amanda's most popular books, Hearts in Cherry Blossom Time.

Perry Trethowan, whose eccentric family (his father's hobby was using medieval torture devices) has been chronicled in earlier Barnard mysteries, accompanies his simpering sister, Christobel, to the congress of romance writers in Bergen, Norway. It seems that Cristabel has "converted her meagre romantic experience and her unbounded romantic longings into three novelettes" and sold them to Bills and Coo, one of top purveyors of romantic fluff.

Perry becomes a confidant of the Norwegian police, who are impressed with his Scotland Yard credentials. He learns that Amanda was a former actress who played her Barbara Cartland role to the hilt, while leaving the writing to anonymous mousy women and shy men.

It's far from hearts and flowers when romance writers get together, Perry discovers. There's no love lost among authors jealous of each other's success, and Perry finds no shortage of suspects.

The denouement is a shocker that strains credibility. Barnard, an elegant stylist and one of the wittiest and most inventive writers of mysteries, is rather subdued in The Cherry Blossom Corpse. His scalpel is not as sharp as it was in his last outing in Bodies, a wicked and delicious satire on the body-building cult. Still, while The Cherry Blossom Corpse may not be prime Barnard, it offers entertaining fare from one of the best in the business.

The Trouble with Taxis

MIKE WEISS, who won a nonfiction Edgar for Double Play: The San Francisco City Hall Killings, now tries his hand at fiction with a mystery introducing Ben Henry, an ex-reporter who drives a cab.

In No Go on Jackson Street (Scribner's, $14.95), Henry takes a dispatcher's call for a taxi and finds that it turns out to be an annoying no-go with no one answering at the address. The next morning he reads in the newspaper that a man has been murdered at that same address. The victim was a popular and influential newspaper columnist.

The taxi-driver angle gives Weiss the opportunity to explore San Francisco streets and capture the back-seat vignettes of riders seen through Henry's rear-view mirror. If the hard-boiled detective devices are familiar -- an ex-wife is always complaining about missed alimony payments -- Weiss nevertheless writes with verve and zest.

Jean M. White reviews mysteries for Book World on the third Sunday of each month.