Adored by generations of writers as well as the likes of Bill Hader and the Coen brothers, this wonder of American literature is four decades old this year. How is it that this absurd and hilarious 1979 novel can say so much about our current collective psyche?

1. “I should have paid more attention to Norma.”

Ray Midge’s wife has run off with a man named Dupree, and they have stolen his car and his credit cards in the process. This is complicated enough, but there are further entanglements. Dupree is his wife’s ex-husband. He and Midge are friends, of a kind. Also Dupree is out of jail on a bail bond that Ray has helped arrange. With reluctance, Ray determines he must set off from his comfortable home in Little Rock and venture across the Mexican border in an effort to set matters straight. This is the animating action of Charles Portis’s The Dog of the South, published 40 years ago and, according to many, one of the funniest books ever written in the English language.

Portis, the reclusive and much-puzzled-over Arkansas-based writer, is best known for having authored True Grit, though each of his other four novels is a timeless classic of a sort. But what sort? Favorable (and reasonable) comparisons have been made to everyone from Cormac McCarthy to Mark Twain, but Portis is too singular and too strange to really explain in this way. A Korean War veteran and former London bureau chief at The New York Herald Tribune, his young life led to some degree of far-flung adventure. He seems not to have thought a lot of this, and left an ascendant career in journalism to move back to his home in Arkansas in 1964 at the age of 31, where he began to formulate his utterly sui generis fictional voice.

Though he was for a time nominally grouped in with the contemporary figures of New Journalism like Tom Wolfe and Gay Talese, the appellation never really fit. As that crowd sought to expand the purview of reportage and blur the lines between fact-gathering and fantasia, Portis had already begun to embark on a different and still more ambitious project. Beginning with True Grit, the author arranged an uncomfortable marriage between traditional narrative tropes and evolving post-colonial sensibilities, his work reflecting an America whose overwrought sense of self had over time gone from point of pride to postmodern joke.

Portis’s protagonists operate at a peculiar frequency and are typically driven to drastic measures by events outside of their own control. There is the enchantingly precocious but unnervingly stoic preteen Mattie Ross in True Grit, out to avenge the murder of her father. There is the doleful country music aspirant and title character of Norwood, conned into delivering stolen cars across state lines against his better judgment. There is the endearingly unquestioning Lamar Jimmerson from Masters of Atlantis, dutifully traveling to Malta to better understand the intentions of a mysterious religious order. And there is 26-year-old part-time student Ray Midge from The Dog of the South, moved on principle to drive to Honduras to retrieve a wife he narrowly wants back and a vehicle he definitely does.

Bill Hader, the former Saturday Night Live cast member and the star and creator of HBO’s Barry, first encountered The Dog of the South following a recommendation from SNL writer Matt Murray, and quickly joined the ranks of Portis’s cult. For Hader, there was an instant recognition of his own off-the-beaten-path upbringing in these characters. “I thought they were funny in the way the people I grew up around in Oklahoma were funny,” he writes in an email. “Dry, irreverent, strange. And the idea of not being able to achieve ‘escape velocity’ was something I think a lot of Midwesterners with big aspirations can relate to.”

In a quixotic gesture, Hader obtained the film rights to The Dog of the South, fully aware of the virtually impossible challenge of bringing such an elusive and internal-monologue-driven novel to the screen in any recognizable form. “It’s incredibly hard to make it a movie. Part of what makes Portis fun is that you’re sitting at a bar with this unassuming guy and he’s telling you this hysterical story, but if you went home and told that story to your girlfriend or husband, it wouldn’t be as funny because Charles Portis isn’t telling it. Unless he’s sleeping with your girlfriend or husband, I guess.”

2. “Odd things happen when you get out of town.”

In a novel full of surreal scenes, one of the weirdest occurs at the beginning of Ray’s journey, just after he has crossed the border and whiled away a night drinking at a local taverna. He repairs to his fleabag motel for some much-needed sleep only to receive an unexpected knock on the door from a hobo drifter he had seen making the rounds earlier in the evening. The hobo is holding a harmonica and sporting a pharmacist’s jacket. The two engage in a confused, strange, and mildly antagonistic dialog and then the tramp hands Ray a business card and departs. The card reads: “Kwitcherbellyachin.” On the back someone has written “adios AMIGO and watch out for the FLORR.”

The episode is very funny but also very disturbing, and perhaps even a little terrifying. It plays like the scene with the Cowboy in Mulholland Drive or an updated version of Elijah’s hysterical warning to Ishmael before he boards the Pequod in Moby Dick. It is also emblematic of the other ontological track on which The Dog of the South and much of Portis’s other work operates: the sub-rosa, the mystical, the conspiracy-minded, and the apocalyptic.

No small part of the comedy in The Dog of the South emerges from the deadpan manner in which straight-shooting, credulous Ray responds to an escalating triage of hallucinatory insanity. Discombobulated by the road and worn by recent hardships, all of Ray’s apertures are open. He begins determined enough to complete his mission but his expedition is rapidly subsumed by the agendas of others. Soon he is plotting at great length and considerable expense to sneak a known criminal into Belize. He finds himself dragooned into a feverish spiritual cross-examination at the dinner table of religious zealots. He experiences a recurring nightmare wherein a truculent 7-year-old boy shouts him down with hoary “quips” like “You bragging or complaining?” and “Welcome to the club, Ray!”

Portis shares something of Thomas Pynchon’s preoccupation with hidden meanings and secret texts, but their takeaways are hardly the same. Pynchon’s boogeymen are entrenched and all-seeing, a powerful cabal of organized malevolence. Portis’s conspirators are low-rent, striving grifters spreading misinformation and invested in the American attitude that they are always just a shuck or two away from being president.

It is tempting to read The Dog of the South as an allegory of America’s foreign military misadventures—the tendency of a discreet mission to turn sideways and eventually become nothing like what its original intention had been. As a veteran of the hopelessly stalemated Korean War, Portis would know something about that. But then it’s tempting to read it a lot of ways. Welcome to the club.

3. “The good salesman must make one more call.”

The Dog of the South takes place in the murky period of American life following Watergate and before Morning in America, and a certain free-floating anxiety over the fraying of the social fabric persists throughout like an unnamed character. Early on we learn that Dupree’s arrest was for writing increasingly abusive letters to the sitting president (presumably Ford or Carter, but ultimately immaterial) and signing them with names like “Dirt Bike Punk” and “Yard Man.” One is given to construe this as less an overtly political act and more like random lashing out—Dupree is not really the sort to harbor a truly coherent philosophy. In the confused detritus of ’60s radicalism, the meaning has been forgotten but the rage remains in place.

Ray is disdainful of the hippies and various counter-culture elements he runs across—“Hippies interfered with my work by stopping me and asking the time. Why did they care?”—but he is equally stressed by the prospect of chance encounters with WWII veterans cornering him with tales of Greatest Generation glories. There is a general sense of untethered anarchy reminiscent of Robert Altman’s woolly American epics of the same decade—an inchoate cynicism about institutions has taken root and is beginning to fester. Yet the era is still pre-modern in many ways, with technology ascendant but not yet oppressive, and the freedom of movement and reinvention still a simple matter of a small bribe to a border guard or a hastily hung sign on the door reading: “I will be out of town for a few days.”

Then there is Dr. Reo Symes.

Symes’s appearance, roughly 50 pages into the book, represents the first outsized disruption in what to that point has been an offbeat but fairly conventional tale of a man in search of his stolen car. In a novel replete with memorable personalities, he is a gale-force wind of bizarre, comic kineticism—“pure nitro.” Appearing uninvited into Ray’s life at a Mexican watering hole and seeking a ride farther south, Symes insinuates himself first into Ray’s vehicle, then into his thoughts, and eventually into his actual business. A grandiose fabulist and a direct literary descendant of Huck Finn’s Duke and King by way of Bob Dylan’s Basement Tapes, he is a medical doctor quick to emphasize: “I’m not in active practice at this time.” He has been recently arrested twice in California, once for disturbing a divine service, the other time for impersonating a naval officer. He is a silver-tongued con man and a codeine enthusiast with big dreams and abhorrent views on race. But most of all he is an evangelist for John Selmer Dix.

Although he appears only in the marvelously unhinged ramblings of Dr. Symes, John Selmer Dix may be Portis’s most crucial creation, the skeleton key that unlocks the trunk of the author’s imagination. As a fully-drawn character who never actually appears and may not really exist, the philosopher-salesman Dix nevertheless provides the novel its wobbly moral context.

For Symes, Dix is the greatest writer who has ever lived, and by no small margin. Anything else is mere “foul grunting.” Also: “Dix puts William Shakespeare in the shithouse.” And so it goes—Symes browbeating Ray about the brilliance of Dix for mile after endless mile of their hard travel. But when Ray finally accedes to picking up the seminal Dix treatise With Wings As Eagles, he discovers only a marginally interesting salesman’s handbook, full of basic aphorisms and nakedly aggressive strategies for closing deals on marks and saps.

Portis’s ease with these sort of book-within-a-book, meta-textual gambits is both a tribute to his vast gifts as a storyteller and a demonstration of his status as a unique hybrid of the classical and the contemporary. As an act of imagination, Dix resides someplace between “The Grand Inquisitor” section of The Brothers Karamazov and a sketch on Mr. Show. It’s also a window into his worldview.

The exaltation of the low-grade flimflammer Dix by the charmingly debased sharpie Symes suggests something about the American character that’s worth pondering. Dix is Tony Robbins and Dix is Joel Osteen and Dix is the Amazon ad running constantly that asks the ostensibly inspiring but ultimately shiver-inducing question: “Can you feel it?”

For Ray, all of this represents a beguiling alternative to his carefully regulated existence. Everything Symes and Dix espouse is either a preposterous lie or some mutant version of the truth papered over by perverse and hypnotically detailed minutiae. To free fall through this sort of ungrounded reality can be entertaining, even out-and-out exhilarating. But to fall is to land, and hitting bottom can be painful. (Watch out for the FLORR.)

How can a glorified sales manual full of worn-out clichés and backward ideas ever truly infect the identity dialog and body politic of America? Atlas shrugs at the notion.

4. “I had not handled myself badly, I thought. And yet there were no results.”

“I’ve recommended The Dog of the South to a bunch of other friends and it’s pretty hit or miss,” Bill Hader remarks when I ask about his attempts at spreading the word on Portis. “One friend said, ‘When does this thing get going?’ and I said it really doesn’t, and that’s why it’s funny.”

This is something you should know about Ray Midge as a narrator and Charles Portis as an author: they are in no hurry. Depending on your temperament as a reader and your patience for digression you may find yourself feeling as frustrated and hamstrung as many of the characters in Portis’s books. Like the broken-down Buick that Ray finds himself piloting, The Dog of the South moves in fits and starts with so many side trips and diversions it is possible at times to forget how or why we are even in Honduras in the first place.

Portis is a yarn-spinner nonpareil, but resolution as such is not his priority. At times he seems to be practically experimenting with something like the opposite. In The Dog of the South, for instance, he pointedly reverses Chekov’s maxim by having Ray ominously conceal a pistol within his luggage in the book’s first act, only to have it harmlessly stolen by a corrupt border agent sometime shortly thereafter. This tendency to build up conflict and then allow it to benignly dissipate before coming to a boil is another of the author’s polarizing mysteries, and the most obvious reason his work is not more widely read. If you find that sort of thing withholding, chances are you will lose interest before long. If you find that kind of thing funny, Portis is your man.

The connection between the Coens and Charles Portis officially dates to the brothers’ 2010 remake of True Grit but his influence informally runs through many of their films. There is something of The Dog of the South in the Dude’s accidental odyssey in The Big Lebowski as well as the antic Wild West chicanery of Raising Arizona and even the sound and fury and no meaning at all hyperactivity of Burn After Reading. (Sharp-eyed fans will note the extended riff on With Wings As Eagles contained in the Portis-like picaresque Hail, Caesar!)

One could argue that the willful lack of resolution is one of the more radical acts a storyteller can engage in, and many have interpreted the ambivalent endings of several Coen brothers pictures as a sort of breaking of faith with audiences who have been indulgent of their whims. Portis inspires this sort of response as well, though in both instances I would argue that what seems like a lacuna to some is actually a reservoir. Which is to say: Ray’s constant distraction and the hijacking of his mission by Dr. Symes isn’t a diversion from the story, it is the story.

Owen King, the best-selling co-author of Sleeping Beauties and Double Feature, who cites Portis as a principal influence, perceives this as evidence of the novelist’s indelible perception of human nature: “This is how people actually behave. Ray upbraids himself constantly for his perceived absence of efficacy, but he is really no more or less efficacious than anyone who finds themselves on an unwelcome errand involving unpleasant circumstances. He likes to read military histories. He doesn’t want to be in the military.”

Hader adds: “I always felt like Midge’s detours were a result of his insecurity. It’s very Midwestern to feel a massive duty to accomplish something that you have no faith in yourself accomplishing.”

Like the Coen brothers’ A Serious Man, The Dog of the South culminates with an unexpected and devastating incursion of nature, an event which suddenly and inextricably alters the frame and makes the preposterous human comedy of Ray, Norma, Dupree, and Dr. Symes feel impossibly small and sad. In the end, Ray prevails, but the victory is Pyrrhic and the result impermanent. He has traveled a great distance and seen a great many things but ultimately failed to address the entropic circumstances that set his life into chaos in the first place.

“There is a strange helplessness to Ray,” King says. “For me, it’s clearest in the way that he keeps engaging with Symes, who is a black hole. Nothing the man says can be believed. Their conversations are hilarious, but what is their value for Ray? They just frustrate him. Yet he keeps plunging in.”

Forty years on, The Dog of the South, with its charismatic con men, farcical border exertions, and black holes of informational nothingness that we plunge into again and again, feels fresh and frightening and funny and prescient. We’re falling and falling. How far down is the FLORR?

Elizabeth Nelson is a Washington, D.C.–based journalist, television writer, and singer-songwriter in the garage-punk band the Paranoid Style.