How great is NBC’s “Hannibal”? Here’s one way of measuring it. I’ve spent the three weeks since its second-season finale rereading the Thomas Harris books on which it’s based, including the ones I disliked the first time, just for the pleasure of sussing out how showrunner Bryan Fuller reworked and occasionally subverted them. (The way Fuller treats the grossly homophobic character of Margot Verger is a master class in how you can revere a source without being beholden to it.)

“Hannibal” shares its title with the third book in Harris’ series — which is also the last one I intend to reread; I love “Hannibal,” but I don’t “Hannibal Rising”-love “Hannibal” — but it’s set before the first. Should the show get so far, Fuller has said its fourth season will cover the events of 1981’s “Red Dragon,” which have already been filmed twice, by Michael Mann in 1986, as “Manhunter,” and in 2002 by, er, Brett Ratner. You could argue that after four novels and five movies, the world has had more than enough of Hannibal Lecter, who over the course of Harris’ novels has been transformed from an enigmatic presence to a lurid cartoon. The key to “Hannibal” is that it kind of agrees.

“Hannibal” isn’t shy about giving its Hannibal Lecter the spotlight, but it’s aware that focusing on aesthetically exacting serial killer is more than a little perverse. Rather than dress up that perversity in the sober garb of Serious Moral Inquiry, Fuller decks it out in an impeccably tailored plaid suit and gives it the run of the joint. If the movies are horror, Fuller’s show is Gothic psychodrama. (Fuller calls it “purple opera.) Harris’ novels paint the world as a rancid cesspool full of venal and conniving creatures, which in the later novels curdles into a kind of sophomoric nihilism. Fuller treats it as a what-if: What would a world populated by killers and would-be killers — a world where a man’s guts are ripped out to serve as the strings for a human cello; where a woman is cut into thing, perfectly even slices and laid out between glass vitrines like a museum exhibit — really look like?

As Matt Zoller Seitz says on his way to naming it the best TV drama of the year:

The subjective storytelling and flagrantly unreal atmosphere make what might otherwise be an unbearably gruesome spectacle not just tolerable but fascinating, at times weirdly stirring, in the way that a depressing opera or brutal fairy tale or Greek tragedy can be stirring. “Hannibal” showcases the most hideous violence ever seen on commercial TV — some of the murders and mutilations make the ghastliest stuff on “True Detective” and “The Following” seem mild — but because it’s all shot and directed with an aesthete’s love of color, texture, and light, it feels a touch abstract, at times defiantly figurative. The blood is photographed as if it were oil paint, the flesh like clay or wood (or latex, which much of it really is). The crime scenes are paintings, sculptures, and multimedia installations.

(Seitz also named the finale, which he describes without spoiling, the year’s best episode, and says he toyed with filling out his top five with four more “Hannibal”s.)

If you were to point out that aestheticizing this kind of vicious brutality is immoral, even grotesque, I’m not sure I could muster an easy answer, except to say that “Hannibal” rarely invites us to glory in its titular hero’s deeds or to share in his distaste for a disorderly world. The novel’s Hannibal kills the rude — a loudmouthed deer hunter or that famously invasive census-taker — and he kills to survive, but the show’s Hannibal, played with gelid panache by Mads Mikkelsen, kills for curiosity’s sake. He’s like “The Third Man’s” Harry Lime with a very sharp set of knives.

However you define the term, “Hannibal” is the most cinematic show on TV — it was mentioned several times in Criticwire’s survey on the best of the year so far — not only because of its precisely composed images but its use of sound (Brian Reitzell’s score sounds like dice rattling in an empty skull), and the way both evolve to tell a story rather than languishing in a static “look.”

With its gory violence and occasional highbrow dialogue, it’s hard to believe “Hannibal” airs on an American broadcast network. But really, it’s hard to believe it’s on TV at all. It’s a marvelous, malificent miracle. Fuller has said he has a seven-season plan for the show, and it would be a bloody crime if he wasn’t able to finish his design.