Chris Marker, the best-known author of unknown movies

By rights, the four-DVD release of his work should rock the film world. At the very least, it presents a primer on wonder and discovery.

"Is this the FBI?" a passerby asks in "The Sixth Side of the Pentagon," looking at the camera.

Of course it isn't. The film's maker, Chris Marker, is not only French but resolutely a man of the left.

In a sense, though, yes: Marker may well be the greatest investigator in the history of film. It's just that his one-man bureau of investigation operates on a philosophical rather than forensic level. He's an essayist who works with a movie camera, a sensibility in constant search of new approaches to inconstant truth.

"The Sixth Side of the Pentagon" (1968), which is about the 1967 March on the Pentagon, is one of a quartet of new DVD releases of Marker films from First Run/Icarus Films.

Their release is a major event - or it ought to be. That's partly owing to their quality, which is very high. Even more, it's because Marker's greatness, which is vast, is wholly incommensurate with any public awareness of him. So the availability of these films amounts to a most impressive primer.

Think of Marker as the very curious love child of Jean-Luc Godard and J. Edgar Hoover - "curious" in both senses of the word. It's not just that he's a master documentarian, which he is. It's the nature of Marker's documentaries: their intense yet free-floating interestedness in the world and the skeptical, wondrously tensile intelligence from which that interestedness springs.

"My work is to question images," Marker says at one point in "The Last Bolshevik" (1993), a film about the legendary Soviet filmmaker Alexander Medvedkin, and another of the four newly released titles. Images aren't the only things he questions. He questions pretty much everything - except animals, whom he accepts unconditionally, and the necessity of distrusting authority.

The other films of the foursome are "Remembrance of Things to Come" (2001), about the French photojournalist Denise Bellon, and "The Case of the Grinning Cat" (2004), which is about . . .

This is the beauty of Chris Marker: His life's work is to demonstrate how limited a word "about" is. "Grinning Cat" looks at a bit of jazzy yellow feline graffiti that began to appear in Paris after the 9/11 attacks. That becomes a point of departure for examining France's 2002 presidential election, the US invasion of Iraq, the nature of radicalism, celebrity journalism, and much else besides.

Each of the new discs includes generous extras. "Pentagon" has Marker's gripping 1973 faux-verite short, "The Embassy," inspired by the overthrow of Chilean President Salvador Allende. "Bolshevik" includes on a separate disc Medvedkin's comic masterpiece, "Happiness." "Remembrance" has a documentary short on Colette, by Yannick Bellon, Marker's collaborator on the former film and its subject's son. And "Cat" includes seven Marker shorts about animals.

The briefest, "Leila Attacks," shows a hilarious encounter between amiable cat and assertive rat. It includes the introductory title card "CHRIS MARKER, THE BEST-KNOWN AUTHOR OF UNKNOWN MOVIES." That has it just about right, unfortunately.

There's no such thing as a typical Marker film. For one thing, they range in length from the 1-minute "Leila" to the three hours of his magnum opus, "A Grin Without a Cat" (1977/1993), a pondering of the failure of the left in the late '60s. For another, he's made films on subjects as diverse as the Helsinki Olympics (his first film, "Olympia 52," 1952), the Cuban Revolution ("Cuba, Si!," 1961), and Yves Montand ("The Loneliness of the Long Distance Singer," 1974).

It's characteristic, then, that his most famous film may be his least typical. A meditation on time and love set in a post-apocalyptic Paris, "La Jetée" (1962) is fictional, consists of almost entirely of still photographs - albeit used with an expressivity few moving images have attained - and is probably best known not for itself but as the inspiration for another movie, Terry Gilliam's "Twelve Monkeys." It's an irony that Marker - a great connoisseur of other directors, as evidenced by "Bolshevik," as well as documentary appreciations of Akira Kurosawa ("A.K.," 1985) and Andrei Tarkovsky ("One Day in the Life of Andrei Arsenevitch," 1999) - must savor.

Relatively few facts about Marker are known, and not all are undisputed. It's agreed that Christian Francois Bouche-Villeneuve was born in 1921, that he studied philosophy with Jean-Paul Sartre in the late '30s, that he served in the French Resistance. But was he born outside Paris, as most accounts state, or in Ulan Bator, as David Thomson reports in "The New Biographical Dictionary of Film"? That's what Marker told Thomson, anyway - and if he wasn't born in Mongolia, he might as well have been. How else to account for an ability to see so much of modern life as intrinsically, if also bewitchingly, exotic.

And did he rename himself, as has been widely stated, after the Magic Marker? It's an ideal pen name, to be sure, and there can't be a filmmaker in whose work words figure so prominently - both the words spoken by his narrators (Marker's a wondrously lapidary writer) and the various titles and intertitles shown in so many of his films. Texts matter to Marker very much - not as much as images, but close. It is, for example, no idle conceit that he organizes "The Last Bolshevik" as a series of "letters" to Medvedkin.

Marker is, in many ways, an aphorist at heart. He has a rare intellectual elegance. He exhibits a whimsy so dry it seems more schematic than whimsical. "You need a lot of tact to do good cooking for desperate people," the narrator says in "The Embassy." "The owl is to the cat what the angel is to man," he says in "An Owl Is an Owl Is an Owl," one of the animal shorts. That aphoristic quality works visually as well as verbally. That's one reason he's able to use still photographs with such eloquence and verve. He responds so eagerly to their economy, and that response helps makes "Remembrance," a succession of photographs, such a delight to watch.

"To be a photographer means not only to look," Marker states in that film, "but to sustain the gaze of others." That remark suggests the fundamental humaneness of his vision. Paradoxically, he's humane without being a humanist. (This is in contrast with his seeming contemporary counterparts as ideological documentarians, Michael Moore and Morgan Spurlock, who are humanists without being humane.) Marker is more at home with animals and ideas and art than with people. Somehow, though, that makes him all the more forgiving, if not accepting, of his fellow humans' failings.

Dziga Vertov is the closest thing to precursor, or peer, for Marker. All Marker's work could bear the title of Vertov's masterpiece, "The Man with the Movie Camera." Their kinship isn't just a shared adoration of film and (what is not quite the same thing) of fact on film. It's also their both being so constitutionally radical, artistically even more than politically.

Yet Vertov, eager Bolshevik that he was, was so absolutely a man of the present. Marker's humaneness takes its most striking form, perhaps, in the very real tenderness he displays toward the past. As the narrator laments in "La Jetée," "The future was better protected than the past." And film, no matter how up-to-the-minute its subject might be, is inescapably a crystallizing of the past. It's "time twice-lived" (also "La Jetée"), the moment first experienced then followed by that same moment seen now. In so honoring the past, Marker also honors the medium to which he's dedicated his life.

"What we call past is somehow similar to what we call abroad," the narrator says in "The Embassy." "It is not a matter of distance. It is the passing of a boundary." Chris Marker, that great cinematic traveler (regardless of whether his journey began in Mongolia or points west) has no betters and few rivals at the passage of boundaries.

Mark Feeney can be reached at mfeeney@globe.com.