With his fourth feature, Alan J. Pakula made a fairly decisive break with what had been his most easily definable thematic concerns up to that point, and thereby created one of the two films that have since absolutely secured his position as one of the great American directors of the 1970s. Prior to 1974, we can track a number of similarities uniting all of his work: a female protagonist, viewed in such a way that the movie could be best considered as a sort of psychiatric analysis of what happens to a person in a given situation. That element isn't completely absent from The Parallax View, except that here, the psyche being analysed isn't necessarily that of the main character, an investigative journalist played by Warren Beatty in one of the great performances of his career; the movie's ambitions are far more crazy than that. The second of the great 1970s paranoia thrillers (it followed The Conversation into theaters by just a couple of months), The Parallax View is also the only entry in that august subgenre that I have seen where the paranoia on display is so richly woven into the very fabric of the movie that it ends up being less an exercise for the characters than for the audience itself; to view this film is to interact with its narrative in such a way that we are the subject, and Beatty's Joseph Frady is in places little more than the vehicle for our own descent into madness.

As with any good conspiracy thriller, most of the fun the first time around is in just buckling in and letting the movie take you where it wants to go, but at the same time, a movie as fraught with ellipsis as The Parallax View becomes essentially impossible to discuss without mentioning, in sometimes great detail, what happens late in the plot. So here's what we're going to do. I will simply posit that this is a truly magnificent '70s thriller, maybe even the very best of all of them, and that if you have any affection for that genre at all, you will certainly love it. So I would like to suggest that if you haven't seen the movie, you should go out and do that sooner rather than later, and this review will be waiting for you when you get that handled. If you have seen it, or don't really mind having an extravagantly twisty conspiracy plot spoiled for you, we'll move along to trying to dissect it a bit; and quite the dissection that will be, for this is one hell of a layered film, thick with formal complexity to say nothing of its dense narrative.

The plot, for those who'd like the recap, is fairly typical stuff early on: a greatly beloved senator (Bill Joyce), who is strongly implied to be an especially left-wing Democrat, is visiting Seattle, when he is assassinated. The official congressional inquiry concludes after careful examination that this was the act of a single depraved gunman who was killed at the scene. Three years later, Lee Carter (Paula Prentiss), a reporter in the Space Needle during the assassination, comes to her colleague Joseph Frady with a terrible suspicion: it seems that the 18 people depicted in a certain photograph (Frady and Carter among them), all of them witnesses to the murder, are dying one by one. Six people so far have had very convenient accidents, and she expects to be next. Frady is dismissive, but in only a day or two, Carter has died of what appears to be a suicidal barbiturate overdose.

Frady knows an unlikely coincidence when he spots one, and he wrangles the permission of his editor (Hume Cronyn) to investigate further. He tracks the goings on to a small town in the Pacific Northwest called Salmontail, where the papers of a murderous sheriff point him to the obscure Parallax Corporation, which publishes a personality inventory for prospective inventories that looks for all the world to be a net for catching violent sociopaths. With a made-up identity in his back pocket, Frady passes the Parallax written test, and goes to their west coast offices for the second part of the interview, and the movie breaks.

I mean this in a good way. Up until now - just a bit past the midway point of a 102-minute film - The Parallax View has been a conventional, albeit unusually well-crafted thriller about a crusading journalist's investigation into a vast conspiracy set to kill a potentially revolutionary politician, and then to silence the witnesses. What happens to him at Parallax shatters the movie's simple generic codes and leaves the last 40-odd minutes of the film as the most sublime, impressionistic depictions of paranoia, not paranoia as a psychological state but more like the Platonic ideal of paranoia as a concept, that I have ever seen or could indeed imagine seeing. Put it another way: the first part of The Parallax View is about paranoia, the second part is paranoia.

The transition is achieved through what I genuinely believe to be one of the truly essential sequences in American cinema in the 1970s. I could describe it, but the description would be flat and pointless: it is a triumph of motion picture language in a way that beggars text description. Indebted in no small part to the Soviet montage theory, in which isolated scraps of imagery are given meaning because of the image preceding and the image following, we are presented with a video flashing certain words, like "Mother" and "Country", along with a couple dozen still images which repeat in absolutely no recognisable pattern, for something around four minutes. This is presented to us from Frady's exact POV; we have become the character, and are experiencing precisely what he experiences.

This abrupt shift of the audience's perspective is just one part of the fairly massive reboot of the film's structure that occurs around this point, and it's not all that we've suddenly been thrust into Frady's mind like we weren't before. The opposite, almost. One of the more interesting peculiarities about the division in the film is that for most of the first half, we know more than the hero does - we learned in the very first scene that there were two killers, for a start. Then, after the video test, Frady knows more than we do; he is taken to a meeting with the Parallax execs that we are never made privy to, and so we spend much of the rest of the film wondering exactly what Frady knows.

As cool as that may be, it's not the really big deal about the last 40 minutes of the movie. Not only do we not know what's going on in Frady's mind - most unpleasantly, we can't be certain, even at the very end of the film, the degree to which he has or has not been brainwashed - we have even less of an idea what's happening. At the end of the film, there's one thing made clear: Frady was a patsy, set up by Parallax to fit the bill of a crazy lone gunman. The $64,000 question is this: when did Parallax start doing that? When did they figure out that he was really a journalist and not a combustible sociopath? There's really no way to answer that question, and that's the terrifying part. For half - hell, most - of the film, there is a strong possibility that Frady, and the audience's understanding of what Frady goes through, is being controlled by people with a vested interest in lying to him and to us - but we can't be certain. I can think of very few films that so thoroughly suggest that most of the narrative is potentially a lie, and none that do it so well.

Of course, The Parallax View had the benefit of coming at a time when America was reeling from disillusionment and conspiracy; though the filmmakers could hardly have planned it (or could they...), Watergate was in full swing when the film was released, and the narrative itself is plainly a reference to the assassinations of the Kennedys and Dr. King (it's impossible to miss how the stern congressional hearings that open and close the film are inspired by the Warren Commission). It is a movie about the sheer terror of living in a time when good people are mowed down at random - a line in the film reinforces this - and thus its very fabric is saturated with the fear that everything really is that chaotic and dark in American life. A grim decade for cinema, the '70s; not many films tore open the reason for that grimness more directly, or with more success.

That success, by the way, isn't just a function of a damn good screenplay - though David Giler and Lorenzo Semple, Jr. certainly wrote a damn good screenplay. The Parallax View is a truly impeccable work of craftsmanship and artistry at every level, the first movie in which Pakula was not just doing a good job shepherding a film but in fact engaging with the language of cinema in fascinating and unusual ways. There's a certain type of shot that I keep noticing in his films, and I've seen it elsewhere in movies of the time, but it's pervasive in The Parallax View: an extreme wide shot, practically an establishing shot, with two characters very small somewhere in the frame, though the audio is as crisp and clear as if we were a foot away from them. There are many reasons to use that set-up, but in the context of this film, it works to isolate Frady (and whomever else he's talking to) in a wide emptiness, stressing the degree to which he's vulnerable at any moment. It's as suspenseful as anything in Hitchcock, which I know to be a trashy clichΓ©, yet The Parallax View is one of the most Hitchcockian films that I think I've ever seen. So many scenes are paced and framed with the greatest elegance and delicacy to produce maximum intensity: a scene on a plane, where Frady watches in a terrifying deep-focus shot as a stewardess comes closer and closer to the warning he's written on a napkin, is one of the best such moments in any '70s thriller.

Though I believe it obvious that the guiding hand of the project was indeed Pakula's (on the strength of its compositions, and the sense that it is a thematically typical work seen through a glass darkly), there are a few particular collaborators without whom it is impossible to imagine The Parallax View working as it does. The chief of this is obviously Gordon Willis, in his second project with the director, turning in (if I can be so unabashedly bold) the best work of his whole career - in the same year as the practically flawless The Godfather, Part II, no less (if you would like to be made very angry, I invite you to consider this statistic: Willis, arguably the best American cinematographer of the last 50 years, received two Oscar nominations, neither of them for his Decade of Miracles, the 1970s). The man rightly nicknamed the Prince of Darkness certainly does not lack for candidates to that title, but by my reckoning, this film witnesses the most tightly controlled use of blacks in his very estimable canon.

But liking Gordon Willis is easy. The other two men who gave so much to the texture of the film are editor John W. Wheeler and sound mixer Tom Overton. Sound in particular is always an important element in Pakula's films, but The Parallax View has a soundscape that must be heard to be understood and appreciated. And the editing, palpably influenced by the French New Wave, blends so effectively with the sound and the visuals that it seems almost impossible to describe it as the work of a separate mind; this is the mark of a strong director, perhaps, and whether or not Pakula thus counts as a great auteur (I'd come down, hesitantly, on the "yes" side of that debate), there is no denying on the strength of this film, even in the absence of any other, that he was among the very best craftsman of his generation. There is a scene between Frady and an ex-FBI friend set on a train ride in Griffith Park, Los Angeles, that should be analysed by every serious student of the artform as a perfect example of the way that cinematography, sound, narrative, and editing can be wholly reliant on each other for the creation of a particular meaning and mood. I should not prefer to do that close analysis here - this review is long enough, and already a day over-schedule - but its genius is right there, ready for anyone ready to go in and just watch, closely.

Form dictates that one must sum up; but how do you sum up something as holistically brilliant as The Parallax View? It is one of the great American films from arguably the finest decade in American filmmaking, inseparable from its time but so elegantly made that it is rendered timeless; preying upon the fears of a very single moment but still as thrilling as any movie ever made in its genre. Basically, this is a flat-out masterpiece, an essential piece of cinema, and one of the most compulsively watchable movies I've seen in many a day.