The flip side of television’s love affair with bodily perfection is its increasing obsession with severed heads, putrefying organs, and the gnarly tangle of bones, nerves, and veins beneath the youthful flesh that often persuades us to turn on our televisions in the first place.

T.S. Eliot’s characterization of the Jacobean playwright John Webster (“Webster was much possessed by death / And saw the skull beneath the skin / And breastless creatures underground / Leaned backward with a lipless grin”) applies equally well to such hugely popular forensics shows as “CSI,” “Bones,” and “Numb3rs,” or to the kinky plastic surgery saga “Nip/Tuck.” Even comparatively wholesome programs like the hospital dramas “House” and “Grey’s Anatomy” provide plenty of gruesome dissections for viewers to contemplate in high-definition close-up.

Now, upping the ante considerably comes “Dexter,” which makes its premiere Sunday night on Showtime. Its hero, Dexter Morgan, brilliantly portrayed by Michael C. Hall (“Six Feet Under”), is a “blood spatter expert” working for the Miami police department who also happens to be a serial killer. The opening shot is of a full moon reflected in a puddle of water. Appropriately, it looks like an old, round skull out of the graveyard scene in “Hamlet.”

A series that asks us to sympathize with, or at least tolerate, a serial-killer hero needs a good explanation for his behavior, and “Dexter” certainly has one. Through a succession of crucially convincing flashbacks we learn that Dexter was a foster child raised, along with his foster sister Debra (Jennifer Carpenter), who also works for the police, by Harry Morgan (James Remar), a legendary old-school Miami cop. Morgan realizes early on that his foster son is an instinctive killer consumed by blood lust.

Further flashbacks depict Dexter as a sweaty, increasingly feral adolescent, his savagery burgeoning even as he bows to the authority of his father, whom he holds in awe. “What happened to you changed something inside you,” Morgan explains to his son, referring to some forgotten or possibly mythical incident in Dexter’s life before he was given a home. “It got inside you too early. I’m afraid your urge to kill is only going to get stronger.”

Having delivered this painful diagnosis, Morgan, who’s seen a few serial killers in his time, decides to “fix” the problem the only way he can imagine. He teaches Dexter to channel his urges by becoming a “moral” murderer who will kill only the deadliest predators — serial killers who have evaded the law. (80% of Miami’s murders, we are told, go unsolved.) He shows him how to do it and how to cover his tracks. As the grown-up Dexter sums it up, “I’m a very neat monster,” and every crime he commits is done in accordance with what he reverently calls the “Code of Harry.”

The echo of “Dirty Harry” is presumably intentional, but there’s no doubting the pleasure Dexter takes in his gruesome work. He is authentically sick, and Mr. Hall, who played a very different kind of death-haunted character on “Six Feet Under,” superbly embodies this cocky, ambivalent creature seething with barely containable desires, who can seem perfectly normal while simultaneously giving you the creeps. He prepares for each assignation as if for a multi-million dollar heist, and every murder — whether of child-killers or serial hit-and-run drivers — is brought off like a flamboyant piece of performance art. If this makes the show seem impossibly dark, remember it takes place in Miami — sensual, multi-hued, bilingual, tropical Miami — a city (at least on television) in which “every night is date night” and “everyone is having sex.” (Except Dexter. As a serial killer, his urges lie elsewhere.) Stunningly photographed by Romeo Tirone, the metropolis comes alive on screen as few cities do, whether we’re looking at trendy restaurants or the treacherous, alligator-strewn swamps beyond its borders. Even the “blood-spatter”charts on the walls beside Dexter’s office desk look like elegant examples of abstract art.

Unlike many other cop shows, the mix of skin tones and races in this Miami police department feels natural rather than forced, as does the casual sprinkling of Spanish phrases into English sentences. And the sentences can be very good. Dexter’s voiceover narration, perhaps taken directly from “Darkly Dreaming Dexter,” the novel by Jeff Lindsay on which the series is based, contains such gems as: “There’s something strange and disarming about looking at a homicide scene in the daylight of Miami. It makes the most grotesque killings look staged, like you’re in a new and daring section of Disneyland — Dahmerland.”

And grotesque they certainly are. A new serial killer is on the loose — the “Ice Truck Killer,” who drains his female victims, minus their heads, of every drop of blood before chopping them up like firewood in precisely arranged sections as if they were avant-garde museum-pieces.

What’s more, the “Ice Truck Killer” seems to know something about Dexter’s secret life, and his corpses appear to be a deliberate taunt to Miami’s “blood spatter expert” — for there is no blood, and therefore no need for Dexter’s services. Dexter is almost comically jealous, like an artist who has just watched a peer make a historic conceptual breakthrough. The fact that he may have been discovered worries him less.

Based on the first three episodes made available to reviewers, “Dexter” is a mordant riff on the media’s aestheticization of murder and a macabre variant on the venerable modernist theme of the outsider. “I fake all human interactions, and I do it very well,” he tells us. Unable to feel love, or even true affection, thanks to his foster-father Dexter knows the value of these emotions nonetheless. He stays close to his unsuspecting sister and tentatively begins a relationship with a traumatized single mother of two. Against the odds, he longs to achieve genuine human communion.

Above all Dexter remains faithful to his father’s memory, cleaving to the “Code of Harry” as to a rock. Ironically, this self-confessed monster may be the most obedient son you’ll find on television. “There are no secrets in life, only hidden truths,” he muses, and one suspects that deep down he is aching to be unmasked.