People have been getting naked in front of movie cameras for as long as there have been movie cameras to get naked in front of. What varies, depending on the context and other factors, is how that nudity is received. Lighting, camera angles, and editing help determine whether something is salacious and dirty, or artistic and acceptable. In some cases, even the relative attractiveness of the actor influences how a nude scene is played: plump, plain-looking women are "artistic"; thin, air-brushed-looking women are "pornographic."

The Unbearable Lightness of Being, which was released this week in 1988, is overbrimming with nude women. (The men they have sex with are nude, too -- but like most films, this one lets its male actors retain their modesty.) It was directed by an American, but its source material, setting, and cast are European; this, and its classical-tinged musical score and pretentious title, makes it feel like an artistic film, not a naughty one. It has far more sex and nudity than, say, Porky's -- yet which film was considered the "dirty" one? I tell you, there's no justice!

The title is unwieldy, immediately crying "critically beloved art-house movie!" The word "being" is not often used as a verb all by itself -- usually you're being something, not just being. The Czech novel, published in 1984 by expatriate Milan Kundera, has its philosophical center on the idea that our lives have no lasting, universal significance, no matter how much we want them to, and that this fact -- this lightness of our being -- can be unbearable. You'd be hard-pressed to guess from that description what actually happens in the film, and you probably wouldn't guess that it would involve Juliette Binoche and Lena Olin being naked all the time.

It sure does, though! They play two of the female satellites orbiting Tomas, a surgeon in Prague in 1968, played by Daniel Day-Lewis. Olin plays Sabina, a mature, worldly-wise woman who has no illusions about the shallowness of her sex-only relationship with Tomas; Binoche plays Tereza, the younger, more naive woman who makes the mistake of marrying him despite having full knowledge of his libertine ways.

Tomas is a man who enjoys sex but not love, passion but not commitment. The book says he was married once and even has a kid; the film omits those details to make him, apparently, a lifelong bachelor. But the women of Prague are more than happy to accommodate him. The first thing out of his mouth when the film begins is "Take off your clothes," uttered to a nurse, who gladly obliges. He issues that command at least twice more over the course of the movie. He even uses the old "It's OK, I'm a doctor" line -- and it works!

But at nearly three hours in length, the story must address more than just Tomas' sexual exploits, entertaining though they may be. Unbearable Lightness is also about the halcyon Prague Spring of 1968 and its quashing by the invading Soviets. In the film, the tanks couldn't roll in at a better time: Tomas is just starting to get chewed out by Tereza for his unrepentant infidelity, and the viewer (this one, anyway) is just starting to grow weary of the too-highbrow, too-sensual storyline. A little social upheaval and arresting of dissidents makes for a nice change of pace. In a neat trick that earned the film an Oscar nomination for its cinematography, we see our fictional characters intermingling with actual footage of the invasion, the tint and coloring of the new images altered to match the old.

The film earned another Oscar nod, too, for its adapted screenplay by director Philip Kaufman and Jean-Claude Carriere. (The latter was previously twice nominated for his collaborations with Luis Buñuel -- seriously art-house street cred.) Kundera, the novelist, generally felt his work didn't lend itself to cinematic translation, but Kaufman somehow got him on board as a consultant on this project. Kundera even wrote a brief poem that Tomas recites, specifically for the film.

What must he have thought of the film, though? So much of his novel, one gathers, is philosophical and internal, while a movie, by necessity, is visual and dynamic. Surely even the best adaptation of such heady material will seem watered down.

As for Kaufman, while this was his first foray into explicit, just-for-grown-ups filmmaking (he had previously made Invasion of the Body Snatchers and The Right Stuff), it would not be his last. Nor was it his only attempt to cinematize tony literature. His next film, 1990's Henry & June, was about another love triangle, between writers Anais Nin and Henry Miller and Miller's wife, and it has the distinction of being the first film to get the MPAA's new NC-17 rating. (It replaced the X, which had come to be associated with pornography rather than legitimate works that happened to contain adults-only material.) He next adapted a Michael Crichton novel, Rising Sun, which has a moment or two of kinky sex, and then, in 2000, made Quills, about the Marquis de Sade. This film, with its reenactments of the infamous writer's smutty stories, feels less like a biography than a bibliography.

Finally, it's worth noting that The Unbearable Lightness of Being marked Daniel Day-Lewis' first major leading role in a film, coming a year before his Oscar-winning turn in My Left Foot. While he's now well known for his "Method acting," it was here that he first began to refuse to break character while on the set. He learned Czech (even though in the film he only speaks English with a Czech accent), and as much as possible lived the life of Tomas during the eight-month shoot. Whether this meant cavorting with multiple nude women in his off hours, I don't know. One assumes he made every sacrifice necessary to understand the character. Hey, an actor's gotta do what an actor's gotta do.

FROM THE TIME CAPSULE: When The Unbearable Lightness of Being was released, 21 years ago this week, on Feb. 5, 1988...

• The top film at the box office was Good Morning, Vietnam, which had already spent three weeks at No. 1 and would stay there for another five. New films besides Unbearable Lightness were Wes Craven's The Serpent and the Rainbow and She's Having a Baby. Moonstruck, Three Men and a Baby, and Throw Momma from the Train were among the other current hits.

• On TV, news programs 48 Hours and America's Most Wanted -- both still on the air today, by the way -- had just premiered. The Wonder Years was brand-new, too.

• It was the sixth week of the year, and six different songs had held the No. 1 spot on the Billboard Hot 100: George Michael's "Faith," Whitney Houston's "So Emotional," George Harrison's "Got My Mind Set on You," Michael Jackson's "The Way You Make Me Feel," INXS's "I Need You Tonight," and now Tiffany's "Could've Been."

• Books on the New York Times Best Seller List included Tom Wolfe's The Bonfire of the Vanities, Stephen King's The Tommyknockers, and Tom Clancy's Patriot Games.

• Poltergeist child star Heather O'Rourke had died four days earlier; singer Rihanna was about to be born. Those two facts are unrelated.

* * * * *

"Eric's Time Capsule" appears every Monday at Film.com. You can visit Eric at his website, which is also light and unbearable.