Horror films have always been prone to navel-gazing. Often neglected and sometimes maligned, the genre has tackled more than its share of Imponderables: what scares us, and why? What happens when you stick a knife into the tender underbelly of faith? What is the face of evil? What does it mean to be a storyteller, and what is the nature of film itself?

John Carpenter has done as fine a job as anyone at exploring these issues. From his landmark Halloween (whose unforgettable final moments offer up a chill that is pure cinema) through such underrated strokes as the paranoiac’s bedtime story The Thing, the anti-Reaganite They Live, and the sublimely creepy Prince of Darkness, Carpenter’s films have been smartly crafted with a real story to tell. It comes as no surprise that his newest horror picture, In the Mouth of Madness,, taps the offbeat yet ubiquitous Sam Neill to anchor a wacked-out tale that pokes sly fun at the Stephen King phenomenon while at the same time offering an odd picture of mass culture.

Neill plays John Trent, an insurance investigator sent on a mission to locate best-selling novelist Sutter Cane. Cane writes horror novels, the kind that make fans of “literary” fiction wrinkle up their noses. We get the impression that he’s a sort of amalgamation of Stephen King and H.P. Lovecraft, with a rabid contingent of fans who grow inexplicably violent — they break windows and bloody one another’s faces scrambling for copies of Cane’s new book at the local shop. A few of those readers, among them Cane’s former agent, wander the streets with bloody hatchets, drooling and raving. The problem is that Cane has vanished, after delivering just a few chapters of his newest manuscript to publisher Arcane. Trent sets off to look for Hobb’s End, the presumably fictional New Hampshire town where many of Cane’s stories take place.

Trent finds Hobb’s End, all right, a small town torn from the pages of Cane’s novels that’s not on any map. And he finds Cane there, as well (Jurgen Prochnow, having great fun as the messianic novelist banging out pages on a manual typewriter as the walls around him sweat and breathe). The story takes a Twilight Zone spin as Trent and Linda Stiles, his companion from Arcane, discover that the good townsfolk are acting out their parts in the books of Sutter Cane. The author is manipulating reality, and he promises that his new book will drive the entire world stark-raving mad. What about people who don’t read books?, one character asks at one point. Well then, he’s told, there’s always the movie (starring John Trent, of course).

Shot for the wide screen and brilliantly visual, In the Mouth of Madness is great fun to watch, with even the requisite cheap shocks doling out a good jolt. Sam Neill is always a pleasure, even when it seems that he’s hardly trying, and his staid characterization is balanced by a slew of icky demonic crowd-pleasing creations that fly in the face of his pronounced skepticism. The down side is that the movie isn’t really about anything, save perhaps the power of the media and the purported dangers of paying too much mind to pop culture phenomena (yawn!). Another old horror hand, Wes Craven (who has been savaged like few other filmmakers for his brutal debut feature,The Last House on the Left), did the genre a bigger favor last year. Even though both films empower the artist, Wes Craven’s New Nightmare went a bold step farther, offering a clever and impassioned defense of the horror film when it needed it the most.

In fact, one might suspect that Carpenter has been sleeping with the neo-conservative enemy, offering up a critique of the mania that could ensue when people read too many scary books. Still, the director is on record opposing censorship, and has always stood up to critics who called his films (The Thing, especially) too violent. We can only interpret the new movie as a love letter to horror fans, a brotherly nudge and wink toward our own cathartic experiences as we sit in the dark, waiting to be scared. At any rate, it’s a tremendous improvement over such Chevy Chase fodder as Memoirs of an Invisible Man, and we can hope that in his next film (a remake of Village of the Damned), Carpenter’s incisive, critical vision will snap back into sharp focus.