BY DAWN’S EARLY LIGHT, By Philip Shelby, Simon & Schuster: 416 pp., $25 A CASE TO ANSWER, By Margaret Yorke, St. Martin’s Minotaur: 336 pp., $24.95 WIDOW’S WALK, By Robert B. Parker, Penguin: 320 pp., $24.95 FLESH AND BLOOD, By Jonathan Kellerman, Random House: 400 pp., $26.95

Suspicion, suspense, thrills and mystifications, perfidious conspiracies concealed in the highest reaches of government and dogged detection syncopated by tenacity are all served up in Philip Shelby’s spellbinding yarn, “By Dawn’s Early Light.”

Shelby Ryder (no relation to her author), a financial analyst in an investment banking firm fired and discredited for having blown the whistle on a criminal scam, is recruited by MJ-11, a small, elite division of the General Accounting Office specializing in scrutiny and pursuit of anomalous activities that may pose a threat to national security. The diviner’s talent and the techniques of competitive intelligence that stood her in good stead on Wall Street are enlisted in hunting down furtive foes of the state and of a society lulled and befuddled by pursuit of money, SUVs and other consumer goods.

Lurid events ensue and are calmly handled, as if foiling a conspiracy to kill the president of the United States to force American foreign policy off course were all in a day’s work. The action grows more vivid by the page, the perils prove more daunting than any that Pauline had to face, the collateral damage vaster. Undeterred by the attentions of a formidable killer or by the casualties clogging public space, Shelby and her fellow MJ-11 scrutineers pursue the lurking treachery and menace that hang half-concealed over Washington. Sharp minds, sharper computers and boundless technology expose insidious influences and vicious bottom-feeders. The complex plot is foiled. The commonweal will be preserved--at least until next time. “By Dawn’s Early Light” is a lively, enthralling fable forcefully told, just waiting to be made into a movie.

No thrills, little mystery and a paucity of suspense mark Margaret Yorke’s excellent “A Case to Answer.” Well-crafted, well-written, easy to read, easy to set aside and take up again, Yorke’s yarn revolves around little people leading little lives in a small country town not far from London, telling little lies (at least most of the time), vaguely committing to fragile, short-lived friendships. It is a banal world of work, work-deprivation, retirement, gardening, hustling, indifference, fish and chips, single mothers, avoidance of eye contact, lusterless loneliness.

Even the crime is petty: car-napping, pilfering, breaking and entering. It is into this colorless context that Imogen, a fat, foolish, sullen teenage girl, out for revenge against dysfunctional parents, causes trouble for everyone around her and brings about the death of the nice elderly lady who has taken her in.

In her ensuing anger, Imogen pretends to be pregnant, which attracts the attention she craves but cures neither her silliness nor her sulks. We are supposed to feel for her, but all I felt was exasperation. The tale, on the other hand, captivates by its fastidious realism. You might find it slow. I’d call it deliberate, and the deliberate drift inveigles one along toward an end that, as in life, is no end at all but makes for good reading.

In “Widow’s Walk,” crime prospers predictably in Boston and environs, crime-hunting thrives and triumphs as it always does in Robert B. Parker’s novels. An elderly banker-millionaire is found shot in bed. Murder or suicide? His stunning airhead of a trophy wife is the prime suspect. Can the blond really be as dumb as she makes herself out to be? Can snitches’ slurs be trusted? Were hit men hired and, if so, by whom? The sexy red-headed lawyer who represents the widow brings in Spenser to winkle out who did the dirty deed; and Spenser, backed up by Hawk and the old team, soon finds himself caught in a cat’s cradle of conspiracies. Suspects (and non-suspects too) begin to fall like leaves in wind before Spenser unravels the web of intrigue, indiscretion, malversation, defalcation and skulduggery. Parker proves fun to read as ever; Pearl the Wonder Dog (ah! woe) is growing old, but Spenser and true love Susan remain reliably resourceful and facetious. One mystery, though, remains unsolved: Why do people have to pause for a shower when danger looms and they are in a hurry?

In “Flesh and Blood,” Jonathan Kellerman’s new thriller, Alex Delaware, clinical psychologist and sleuth extraordinaire, is back on the warpath. One of his old patients, Lauren Teague, has been shot and dumped in an alley off Sepulveda Boulevard. As Alex and his sidekick, LAPD detective Milo Sturgis, investigate her execution-style murder, they uncover her penchant for stripping, her entrepreneurial lubricity, her prudent investments, her long-standing hang-ups and carousel affairs. The inquiry into who might have offed the precociously promiscuous university student, who was also nervous, needy, neurotic and pining for a father, or at least a father figure, broadens to include a notorious Hollywood madam, a millionaire sex tycoon and his brood, several members of the university faculty and another girl student who mysteriously disappeared long before.

Delaware drives a lot, broods a lot and exasperates his girlfriend. But fewer clues turn up than reflective ruminations, and the investigation treads water. Dialogue is almost as clever as ever; action is more muted than words; violence is brief and spare; final revelations are convulsive and unexpected. Kellerman is not exactly at the top of his form, though near it. If you’re a hardened Delaware addict, you’ll go for the familiar formula. If you are not, you can give it a miss.