This is part of The Ringer’s Movies of 2007 celebration, which will look back on the brilliant, influential, uproarious, and unsettling films of that deeply influential year. You can read about the "gastronomic delights" of Ratatouille, here.

The American modernist composer Charles Ives referred to his 1906 work "The Unanswered Question" as a "cosmic drama," a metaphysical debate set to music with each point of view represented by a different group of instruments. The piece begins with an eerily beautiful string arrangement that is repeatedly punctured by the anxious, probing notes of a solo trumpet; in his program notes for the piece’s first public performance in 1946, Ives wrote that the trumpet’s intrusion voiced "the perennial question of existence," while the agitated whirl of woodwinds in its wake embodied futile attempts at a reply.

In terms of compositional technique, Ives’s collage represented a bold collision of tonal and atonal styles, which is why it’s often cited as one of the key works of 20th century classical music. In terms of its outlook, however, "The Unanswered Question" vibrates with a deep and affecting humility. Its three instrumental perspectives never quite harmonize; the silence that greets the final trumpet figure is the auditory equivalent of a hard cut to black. It’s the work of a master motivated to say that in the final analysis, he doesn’t really know anything at all.

That same lonely solo trumpet finds its way into Zodiac somewhere around the 30-minute mark; in a film whose soundtrack is compromised almost entirely of period pop songs, its plaintive brass tone stands out. It’s a subtle masterstroke of David Shire’s musical score — which was commissioned late into the editing process of a film that originally wasn’t supposed to have one — that it interpolates Ives’s piece at crucial moments, recasting David Fincher’s sixth and by-far greatest feature as a procedural riddled with unanswered questions: a horror movie punctuated with a question mark.

More than any American movie of the past decade, Zodiac accepts and embraces irresolvability, which may be why it’s so hypnotically rewatchable. If it’s a cosmic drama, it’s one that works on macro and micro levels. Its depiction of the hunt for the most notorious and mysterious serial killer of the 20th century is at once suggestive of larger cultural shifts while also being detailed down to the inch. Reviewing the film for the Village Voice in 2007, Nathan Lee perceptively called it an "orgy of empiricism," noting that for the first time, Fincher’s micro-managerial directorial style was being applied to historical material. The same fanaticism that held up production on Alien 3 and pushed Fight Club over budget was now angled as a guarantor of authenticity.

Fincher is a scrupulous blue-printer with a reputation for control freakery. What Zodiac represented was an attempt to leverage those skills in the service of ambiguity — to make a work more open to interpretation than its predecessors. In Se7en, Brad Pitt finds out whose head is in the box; in Fight Club, Edward Norton finds out who’s really in his head (spoiler: it’s Brad Pitt). In those films, Fincher orchestrated sharp, jagged storytelling twists that tore their narrative universes apart. In Zodiac, the fabric of reality is stretched so tight over the action that it threatens to break at any moment. Except that it doesn’t. The twist is that there isn’t one.

In order to take the true measure of Fincher’s achievement, it’s worth comparing Zodiac to Se7en — and not only because its predecessor’s world-beating commercial success was routinely used to pummel Zodiac when it flopped at the box office in March 2007. Se7en’s mix of urban grit, MTV glitter, and Biblical grimness felt like something new — a Trent Reznor noir — but Fincher and screenwriter Andrew Kevin Walker’s shrewdest calculation was to capitalize on the early ’90s vogue for messianic murderers. "The psychotic serial killer," wrote Chicago Reader critic Jonathan Rosenbaum in his skeptical review of The Silence of the Lambs, "is the essential religious figure of our time: saint, guru, seer, and soothsayer rolled into one."

What many viewers found seductive about Se7en was the way that its visual style basically enshrined the point of view of its Lecteresque antagonist. As framed by Fincher and photographed by Darius Khondji — the brilliant, Iranian-born cinematographer who got the gig after working with the director on a Nike commercial — Se7en’s world seemed exactly as corrupt and corroded as Kevin Spacey’s John Doe suggested.

"You’re no messiah," snarls Pitt’s Detective Mills. "You’re a movie of the week. You’re a fucking T-shirt, at best." He’s got the moral high ground, but Doe has the upper hand. The filmmaking in Se7en is perfectly aligned with its villain’s perceptions. Each exquisite corpse on display represents a collaboration between two masterminds: the character and the director.

There is no such identification in Zodiac, which only ever adopts its villain’s point of view once, and even then, in an extremely specific way: At the end of the opening credit sequence, the camera is placed in a mail cart containing the first coded missive from the Zodiac to the editors of the San Francisco Chronicle. It’s a marvelously lo-fi visual effect, but it serves a crucial purpose all the same. It creates the impression, which is sustained with incredible focus and concentration for the film’s nearly three-hour running time, that the Zodiac Killer is as much an ephemeral, disembodied phenomenon as an actual flesh-and-blood person.

The irony is that it was the inability of various institutions, including the media and the police, to definitively identify the man that allowed this malevolently free-floating persona to take hold of the wider imagination. Zodiac is less a movie about a serial killer than it is a movie about the idea of a serial killer, a fine distinction that transforms it into Se7en’s spiritual prequel, as well as a kind of coded apologia for the earlier film’s success. Where Se7en shrewdly exploited the public fascination with charismatic murderers to create a memorable piece of pulp fiction, Zodiac examines the roots of that fascination: It’s a return to the primal scene.

In this case, the primal scene is also a crime scene, and Zodiac’s opening sequence may be its greatest — one of the most intricately conceived and executed cold opens in recent memory and perhaps the best evidence of Fincher’s multileveled artistry. Zodiac was not only the director’s first film based on a true story (anticipating The Social Network), but also his first period piece and his first time shooting digitally, and these three threads — history, veracity, and technology — are simultaneously set against each other and intertwined in an Ives-like pattern from the first shot.

Or, actually, from even before the first shot. Zodiac begins with the old Columbia Pictures logo, treated digitally to give the impression of old 35 mm stock. Certainly, plenty of movies have employed similar tricks to pay homage to different eras of filmmaking (exactly one month after Zodiac’s premiere, Quentin Tarantino and Robert Rodriguez unleashed the strenuously retrograde Grindhouse), but Zodiac makes a complex fetish out of its play with formats. Throughout the film, cinematographer Harris Savides replicates the grainy appearance of mid-’70s masterpieces like Alan J. Pakula’s All the President’s Men, an act of mimicry that places the action squarely in both the historical and cinematic past and imparts a sense of realism that is, ironically, as manipulated as (if not more so than) anything in Se7en’s hellish metropolis.

"Based on true events," reads the white-on-black title card that comes next, reinforcing the impression of verisimilitude but also nodding to the fact that at the beginning of the 1970s — the period in which Zodiac begins, with a dateline of "July 4, 1969" overlaid on its astonishing aerial opening image of fireworks in mid-explosion — most horror movies made a point of advertising their ripped-from-the-headlines inspirations. Taking their cues from Psycho’s vague connection to the crimes of Ed Gein, films like The Texas Chain Saw Massacre and The Last House on the Left tried to sell themselves as docudramas rather than simple gross-outs. What Fincher understands — and expresses brilliantly here — is how the visual language and moralistic meanings of the period’s horror films, steeped in the link between sex and death and often set in the world of teenagers, were derived from larger cultural anxieties.

The boy and girl driving off together into the dark for an Independence Day date look as wholesome as a Norman Rockwell painting, but there are cracks in the façade. There’s no innocence here: She’s a married woman and he’s a nervous wreck. As the Zodiac’s first recorded victims, Darlene Ferrin and Michael Mageau (who survived his wounds) are fated to be footnotes to history, and yet as Fincher films them — cruelly slowing down the action a la Warren Beatty and Faye Dunaway’s in Bonnie and Clyde — they become emblematic figures: not tragic outlaws but collateral damage as something new and terrible emerges in the wake of the Summer of Love.

The use of Donovan’s peace-and-love anthem "Hurdy Gurdy Man," about the singer’s visionary encounter with a musician singing "songs of love," is a contrapuntal music cue as weaponized as anything in Stanley Kubrick’s repertoire. By picking up on the barely concealed darkness in the song — which drenches its melody and the singer’s voice in ghostly reverb and echo — the scene turns a hippie’s dream into a nightmare. "[The song] may have been inspired by the Maharishi," writes Kevin Courrier in Artificial Paradise, "but the abiding spirit on the record could just as easily be [Charles] Manson. … Donovan composed a song that was less a celebration of spiritual renewal than a harbinger of bad tidings."

It’s within this creepy countercultural context that the San Francisco of Zodiac really resonates — another example of how Fincher uses reality to his advantage without deviating from the record. It’s hard to say whether the city’s status as the most paranoid location in American cinema is a case of filmmakers channeling something that’s already in the air or if the city started taking cues from Vertigo almost 60 years ago. Either way, the Bay Area has starred in a disproportionate number of classic thrillers: everything from Experiment in Terror to The Conversation to Basic Instinct.

Fincher, who grew up in nearby Marin County, California (down the street from George Lucas), said in interviews that the geography of the Zodiac murders gave him a personal stake in the story: "If you grew up in the Bay Area, you had this childhood fear that you sort of insinuated yourself into it," he told one interviewer. "What if the killer showed up in our neighborhood?"

The civic reference points in Zodiac feel universal because of how they connect to our collective film-going experience. A digitally assisted time-lapse shot of the Transamerica Pyramid being constructed doesn’t just mark the passing of time, it calls back to the building’s fog-shrouded cameos in Philip Kaufman’s Invasion of the Body Snatchers. A predatory overhead view of a taxi cab winding through the streets evokes the voyeurism of Vertigo. The central role of the case’s lead investigator, David Toschi (Mark Ruffalo), places the film in conversation with Bullitt and Dirty Harry — both of which based their eponymous, loose-cannon cops on the media-sensation detective.

Bullitt was made before Toschi was assigned to the Zodiac case, while Dirty Harry borrowed much of its plot, as well the astrological moniker of its villain — a sniper who calls himself "Scorpio" — from front-page coverage: It even includes a scene where Scorpio sends a letter to a San Francisco newspaper outlining his plans. Fincher engineers a wonderful hall-of-mirrors trick when he shows Toschi at the premiere of Dirty Harry, storming out abruptly, frustrated at seeing his daily grind sensationalized onscreen — we’re watching an actor in a movie playing a real person who’s angry at having his life being turned into a movie. A picture is worth a thousand words, and when Toschi leaves the theater, he pauses on the steps and is framed beneath a lobby poster that makes it looks like Callahan’s gun is pointed right at his head.

Toschi isn’t the only character in Zodiac with an onscreen alter ego. The first break in the case comes when the Chronicle’s cartoonist, Robert Graysmith (Jake Gyllenhaal), connects a stray line in one of the killer’s letters about "hunting the most dangerous animal" to the sociopathic sharpshooter Count Zaroff in the 1932 film The Most Dangerous Game. "Is that Zaroff with a ‘Z,’" snarks crime reporter Paul Avery (Robert Downey Jr.), who’s baffled and bemused by the younger man’s encyclopedic movie-nerd recall. Later, when publicity-hungry attorney Melvin Belli (Brian Cox) agrees to appear on live television to field a phone call from the killer, the news anchor recognizes him more for his previous prime-time cameo: "I loved your Star Trek."

These references are not just texture; they’re at the heart of Zodiac’s project, which is to chart the slippage between reality and pop culture that turned a murderer into a multimedia star. James Vanderbilt’s screenplay gives some of the credit to the Zodiac himself (or maybe themselves, since the theory of copycat killers is very much in play in the film’s presentation), positioning his publicity-mongering tactics as ahead of the curve. And while the film is set in an analog era, Fincher teases out the post-internet implications of an anonymous person firing off cryptic messages to be decoded by anybody with the patience to play along.

Whenever Fincher shows the killer at work — as in the opening scene — he’s a vague, unformed shape, played by multiple actors to allow for the possibility of more than one person taking credit for the crimes. He’s far more frightening once he disappears from the film, which, in another departure from Se7en’s carefully engineered final confrontation, happens early on. Because Zodiac sticks to the facts, it’s almost entirely focused on aftermath. There is no onscreen violence of any kind in its second or third hours. Fincher keeps the tension up by conveying presence through absence, as if the killer has transcended physical existence altogether. A mid-film montage showing ominous notes superimposed over various San Francisco locations suggests that after his appearances in print and television, the Zodiac has gone viral.

Here, Fincher has each of his lead actors read one of these letters out loud, calling attention to the film’s unusual, tripartite structure. Zodiac is a movie with three protagonists, each of whom poses the same unanswered question from a slightly different angle. What begins as a study of how the media covered the case — with special emphasis on how Avery’s vainglorious desire to become part of the story backfires — shifts gears to become a police procedural, with a Toschi-heavy middle section, before ultimately casting its lot in with Graysmith, an amateur sleuth who has no real obligation to the case but pursues it even more obsessively than the professionals on either side of him.

There are gradations to the three men’s respective quests. Where Avery is primarily in it for glory and Toschi is bound by duty, it is Graysmith, the amateur cryptographer, who is most naturally on his quarry’s wavelength. It’s clear that Fincher identifies closely with Graysmith’s largely left-brained interest ("I like puzzles," he tells Avery brightly during their first encounter). Gyllenhaal famously had his issues with Fincher’s "Pavlovian" directorial tactics, but his performance, while less flashy than Downey’s or as carefully studied as Ruffalo’s, is nevertheless key to the film’s effect. It’s been said that Gyllenhaal is best when he’s playing innocence corrupted, and even if Graysmith doesn’t betray the same signs of psychological ruin as Avery (who spends the last third of the movie sequestered on a houseboat playing Pong) or Toschi, the way that his wide, staring eyes gradually narrow into tired slits conveys the toll of his self-inflicted sickness of data overload.

The most perfunctory thing about Zodiac — its only glaring flaw — is the way that it dramatizes the toll that Graysmith’s investigation takes on his relationship to blind date turned second wife Melanie (Chloë Sevigny). Fincher didn’t truly throw himself into portraying domestic dynamics until Gone Girl, and Sevigny’s thankless role yields a disposable performance. What’s harrowing isn’t the question of what Graysmith stands to lose by chasing leads, but rather what he might find if he succeeds. The film makes a point of showing that while the Zodiac’s victims were chosen at random, Graysmith willingly puts himself in the crosshairs: He’s playing the most dangerous game.

It’s arguable that the scene in which Graysmith questions the former employer of one potential suspect shades into creep-show shamelessness, complete with darkened basement and dark-and-stormy-night sound effects. It’s the only time that Zodiac feels like it’s capitulating to conventions instead of doing a clever end-around. But it’s redeemed by his subsequent encounter with Arthur Leigh Allen (John Carroll Lynch), the subject of Graysmith’s 1986 book and the man who the film comes closest to calling out as the Zodiac even as its power resides in the thin slivers of doubt it carves out in the process.

In the second-to-last scene, Graysmith goes to see Allen, who is now working at a hardware store, years after he was first picked up for questioning by Toschi and his colleagues. His inquisitive gaze is met by a terrifyingly unreadable expression. Face-to-face with the man who might be the Zodiac, he’s further from certainty than ever before, and his quick exit is even more mysterious than Allen’s face. Is he terrified? And if so, is he scared that he’s gotten his man, or that he hasn’t?

There’s an equally devastating ambivalence in the film’s coda, which takes place in 1991 in an Ontario, California, airport, where Mike Mageau — the teenage boy from the first scene — is shown a photo of Arthur Leigh Allen, whom he identifies as the Zodiac once and for all. "The last time I saw this face was July 4, 1969," he says. "I’m very sure that’s the man who shot me."

The credibility of this statement is compromised by the fact that Mageau is literally not the same person that he was in the film’s first sequence: He’s being played by a different actor, Jimmi Simpson, whose haggard, haunted expression makes him a mirror of the film’s three heroes. One on level, the casting makes practical sense. It’s 22 years later and most actors couldn’t convincingly play that age range, with or without makeup. But in a movie where every other character is played by a single actor as they get older — except for the Zodiac himself — it’s a jarring switch, what movie fan Tyler Durden would call "a change-over." It suggests that the Zodiac’s final victim is certainty itself, a body count that just keeps growing with the passing of time.

An earlier version of this piece incorrectly stated the setting of a scene as a Toronto airport; the scene is set in an airport in Ontario, California.