And with the release of Christopher Nolan's “ un-restored restoration ” of the 70 mm version, now at the Somerville Theatre (through June 14) and soon to be at the Coolidge (June 15 to 24), it’s as good a time as any to reflect on why it’s the greatest — the Muhammad Ali of movies.

But it was also a turning point in film with the release of “2001: A Space Odyssey,” which has both enthralled and bored audiences for 50 years. Count me not only among the enthralled; count me among those who say it is the greatest movie ever made.

In many ways 1968 was the year everything started to go bad. Martin Luther King Jr. and Bobby Kennedy were killed; Richard Nixon was elected; and the history of the United States was changed forever , particularly the history of American leadership.

I have to admit that personal history plays a part. At the end of my junior year at Boston University my newly-promoted friends and I put our first issue of The News, the main campus newspaper, to bed. It being the ‘60s, it was no time to put ourselves to bed. So off we went to someone’s apartment to celebrate with the era’s inebriant of choice.

Channel 7 in Boston was then showing reruns of “The Twilight Zone” in what for us was prime time — 1 a.m. We soon got talking about our favorite episodes: "Nightmare at 20,000 Feet" with William "Captain Kirk" Shatner, "The Invaders" with Agnes Moorehead, "A Stop at Willoughby."

In the middle of the sci-fi/horror delirium and marijuana haze somebody mentioned that this new movie was playing at the Boston Cinerama theater, which had the exclusive rights to the 70 mm format in which "2001" was shot. (A 35 mm version would later play at the Paramount.)

Stanley Kubrick in 1975 on the set of "Barry Lyndon." (AP)

Maybe somebody threw out the name of screenwriter Arthur C. Clarke, whose “Childhood’s End” I had read in high school. Maybe somebody threw out the name of the director, Stanley Kubrick. The name wouldn’t have meant much, despite “Lolita” and “Dr. Strangelove.” I, and my fellow cine-snobs, didn’t want to see anything that hadn't played at the Nickelodeon or other art-house precursors of the Kendall. And if it was American-made, not much besides Arthur Penn’s “Bonnie and Clyde” was worthy of discussion with the great gods Bergman, Fellini, Godard and Truffaut. Even though Alfred Hitchcock had been re-evaluated as a major Anglo-American artist by the auteur intelligentsia, the news hadn’t reached Cambridgeport. And, besides, his best work was behind him.

All of which is to say that I didn’t have high expectations when we decided we would all camp out at the apartment and venture down to what was then Boston's Combat Zone the next morning for the first showing of “2001: A Space Odyssey.” The fact that Cinerama was used mostly for silly travelogues and empty epics added to the low expectations. (Actually, the film wasn't shot in Cinerama, but certainly benefited from the three-screen format.)

I remember being more exhausted than high as we walked into the mammoth Boston theater, greeted by the disorienting avant-garde chantings of Ligeti’s “Atmospheres,” which served as an overture to the movie and should have been a tipoff that not only weren’t we in Kansas, anymore, but that all our expectations about what a movie and what popular culture could be were about to be shattered by Mr. Kubrick.

Frankly, he had me at Nietzsche. Or at least Richard Strauss’ majestic evocation of “Thus Spake Zarathustra” with the moon-earth-sun alignment that opened the movie. And then one cinematic touchstone after another: the deep crimson sunsets; the ape men and women; the frightening first appearance of the monolith with the return of eerie Ligeti music; the discovery of weaponry; the bone-turned-spaceship; the elegance and peerless futuristic matching shots of “The Blue Danube” by the other Strauss; the smart science; more than 20 minutes at the beginning and end of the movie without a word spoken; the first iPads; the first flat screen TVs; actors in 360-degree rotation; artificial intelligence; hostile artificial intelligence; the mind-blowing “Jupiter and Beyond” hallucinogenic segment; and then full-circle back to Richard Strauss and the astronaut’s metamorphosis into — are you kidding? -- a star child.

The space shuttle approaches the space station, an example of Kubrick's matching the elegance of "The Blue Danube Waltz" to the visuals. (Ho, Turner Entertainment/AP)

The individual parts of the Kubrick playbook have served directors in good stead ever since, though few would have the power and imagination to put them all together and pull off the “visionary thing." (Steven Spielberg has the power, not the imagination. Darren Aronofsky has the imagination, but not the ability to tell a coherent or engaging story.) Kubrick ruthlessly refused to settle for what proven veterans had given him. He did away with several iterations of Clarke's narration as if to illustrate Hitchcock’s dictum not to tell what you can show. He completely junked soundtrack superstar Alex North's music in favor of the Strauss boys and Ligeti. Nice guys and gals don’t always finish last, but Kubrick’s insistence on putting the movie ahead of personal considerations illustrates that art often demands a certain ruthlessness. On the downside, in his quest for perfectionism in how the astronauts' flotation was shot, he nearly killed a stuntman or two.

At the same time he was open to ideas from anyone on or off the set. From the tea boy to a visiting mime, Kubrick incorporated others' ideas about where to shoot scenes; how the ape men should be portrayed; how HAL, the AI computer, could eavesdrop on the astronauts. Read Michael Benson’s superb new book, “Space Odyssey: Stanley Kubrick, Arthur C. Clarke and the Making of a Masterpiece,” for all the information.

The astronauts (Gary Lockwood and Keir Dullea) worry about HAL's "mistakes." (Courtesy of Warner Brothers)

But to what end, all these formal touches? When that initial viewing was over someone said, as many have since, “I loved it, but I’m not sure I get it.” Stephen Davis, who would later write biographies of several rock stars — and Howdy Doody — turned to our compatriot as we were walking out of the theater and tersely but sagely pronounced, “Evolution.”

Truer word was never spoken. You can overlay any number of interpretations, but ultimately it comes down to humanity's ascent from the apes to a higher form of being. Thus spake Nietzsche as well as Kubrick and Clarke. There have been few late-20th or early-21st-century films that have attempted such an optimistic view of where we might be headed.

Kubrick was certainly never so rosy again. The species couldn't get much worse than in his follow-up film "A Clockwork Orange" or in "The Shining" and "Full Metal Jacket." And Ryan O'Neal and Tom Cruise could have used a monolith to show them the way in their odysseys, "Barry Lyndon" and "Eyes Wide Shut."

Don't get me wrong. I love all those movies. Fifty years after "Space Odyssey" I'm more inclined to share Kubrick's pessimistic view of human horrors. (What would he have made of today's tribalism; Jack D. Ripper from "Dr. Strangelove" could be secretary of state.)

Still, after going back to its first showing at the Somerville Theatre, this time with just one friend and a shared pilsner as my inebriant, it's "Space Odyssey" that leaves me in awe of Kubrick as an artist and of "2001" as filmmaking's highest achievement. As much as I love being an arts critic, I'm kind of happy that part of his legacy is, historically, having the last laugh on such hallowed critics as Andrew Sarris (my hero), Pauline Kael, Renata Adler and Stanley Kauffmann, who all hated the film. (It should be humbling to see fellow critics proved so wrong in the end ... but it isn't.) Media maven Marshall McLuhan and filmmaker Andrei Tarkovsky, who also damned the film, don't look so hot either.