The Marx Brothers, a Broadway phenomenon of the 1920s, triumphed briefly as film stars: First in the early 1930s, peaking with the mediocre “Monkey Business”; then in the mid-1930s, with “A Night at the Opera,” the audience having ignored their intervening masterpiece, “Duck Soup.” Their true peak, however, occurred posthumously, in the 1960s and 1970s, when a generation raised on televised movies adopted the Marxes as simpatico anarchists and took them off to college. The long-surviving Groucho crowned the revival with his 1972 Carnegie Hall show, his first appearance on a New York stage since 1929. Many books and screenings followed, yet 30 years later it must be conceded that the best chance an undergraduate has of encountering the Marxes is in a film studies course.

That dreary thought is made harder to bear by a suspicion that classroom showings are encumbered by as many footnotes as Dryden and Pope – equally sly comics of an earlier day. The “strange interlude” joke parodies the title and technique of a Eugene O’Neill play. “Monkey-Doodle-Doo” is

Irving Berlin’s take on the rejuvenating powers of monkey glands. “The Trial of Mary Dugan” was a 1929 Norma Shearer flick. “Ten cents a dunce” refers to a Rodgers and Hart song. And so on and so forth, line for line, pun for pun. The Marxes transcend the details, however; they are funny men who get funnier as the topicality of the writing recedes in importance. I confess that after a lifetime of Marxist contemplation, I have no idea what the following speech from “Horse Feathers” means: “Scientists make these deductions by examining a rat or your landlord who won’t cut the rent. And what do they find? Asparagus.” One learns to live with these things.

The two jokes central to their work do not date and have never been successfully emulated. No one in Marx Brothers movies knows the brothers for the lunatics they are; at the same time, the brothers themselves fail to comprehend the futility of the chaos they beget. The first joke requires supporting casts to stand around like mannequins as the occasionally sadistic clowns disport themselves. It obliges allegedly sane characters to hire Chico and Harpo as spies, managers, or football players, and to appoint Groucho college president, sanitarium director, or hotel manager. It inclines wealthy dowagers – played by the imperturbable Margaret Dumont, who responds to each dig with a recyclable look of mild umbrage – to romance the lustily impotent Groucho. The second joke nails their isolation, adding a touch of mordant pathos as they age. The chase and leering remark is as intimate as they can get – with one impromptu exception. Near the end of “Duck Soup,” Harpo actually grabs Dumont’s buttocks. She turns, aghast, only to end as the object of greater abuse in what may be the funniest closing shot ever.

In the five pre-production code films made for Paramount between 1929 and 1933 and collected in Universal’s new DVD set, they insult everyone, including the stiff romantic leads, whose awkwardness adds to the fun. In their postcode films, they become enablers for young lovers, who in turn treat them as amusing children or strange uncles. An insensible cliche in movie criticism downgrades the first two films, “The Cocoanuts” and “Animal Crackers,” as photographed stage plays, but that is their strength. The corny dancing; the hapless actors (in a movie theater, Oscar Shaw gets a laugh each time he show his prissy smile in “The Cocoanuts”); the stationary shots, which force actors to turn around so we can see who they are and catch the dancers up-skirt; and the many uncorrected flubs contribute to an unparalleled spontaneity. The scenes had been endlessly rehearsed on stage, yet the films feel like middle-school theatrics in which only the Marx Brothers wield real power, thus enhancing their roles while reducing every one else to bland stereotypes. The problem with “The Cocoanuts” is Berlin’s “When My Dreams Come True,” which is reprised relentlessly like bad operetta – as happens with dull songs in “Horse Feathers” and “A Night at the Opera.” To paraphrase Groucho, he has to stay but we can fast-forward.

While much credit has been given the team of writers recruited for the Marxes (George Kaufman, Morrie Ryskind, S.J. Perelman, among them), insufficient respect is accorded the songwriting team of Harry Ruby and Bert Kalmar, who not only protected them from operetta but allowed them to lampoon it with unequalled ferocity, beginning with “Hooray for Captain Spaulding” in “Animal Crackers” and rising to greater Gilbert and Sullivanian heights with “I’m Against It” in “Horse Feathers” and the magnificently hitless score of “Duck Soup,” including “Freedonia Hymn” and “The Country’s Going to War,” which turns into a full-bore minstrel show complete with xylophoned helmets, “All God’s Chillun Got Guns,” and “Turkey in the Straw.” Director Leo McCarey packed so many visual and verbal gags into 68 minutes that the film plays like a sustained inspiration. Its most famous moment, though, is rendered in silence – the broken mirror mimicry, a bit Mc-Carey originally worked out for a Charley Chase silent film (now available on Kino’s “The Charley Chase Collection”). “Duck Soup” is peerless.

But “A Night at the Opera” and “A Day at the Races” – the first films they made for MGM, with big budgets and the humorless director Sam Wood, who concentrated on romantic ballads and a grueling peasant dance – come close enough to win a crate of Cohibas. Here are the stateroom scene, the contract dispute, the racing manuals, and much more, including the only great musical number in a Marx Brothers film not involving the brothers: “All God’s Chillun Got Rhythm,” in “A Day at the Races,” sung by the incomparable Ivie Anderson, accompanied by the Crinoline Choir and (physically if not musically) members of the Duke Ellington orchestra. This scene was cut from television for years and decried as racist by sensitive white liberals. They are free to skip it; the rest of you can head straight for chapter 22 to see Anderson in clover; racism manifested itself less in the Catfish Row stereotypes than in the absence of offers to bring her back to the screen.

The later films are increasingly uneven, but often savory. The stage play “Room Service” and “The Big Store” are tiresome, but “At the Circus” merits closer inspection (despite “Two Blind Loves,” a song so awful it is perversely fascinating) for comic bits, including a brilliant closer, and its reverse sadism aimed at Groucho. “Go West” takes a long time breaking loose, but the underrated “A Night in Casablanca,” free of songs, has more memorable lines (including Groucho’s riposte to Chico, “I don’t mind being killed but I resent hearing about it from a man whose head comes to a point”) than their previous four films combined. It begins as straight drama for three minutes until the famous first sight gag; if only it didn’t dissipate in an endless airplane chase.

The few extras in the Universal box are negligible, but the prints are mostly excellent, except for the “lost” scenes long ago excised from “Animal Crackers” and the boudoir episode in “Horse Feathers,” which is mangled by more than a dozen splices – hard to believe they couldn’t find better sources for that one. The Warner Bros. box is fat with worthwhile extras, including Robert Benchley shorts and rare cartoons, though one wonders why they omitted the brothers’ last film, “Love Happy,” which is admittedly dire but no more so than “The Big Store.” The Warner Bros. prints are superb – even lesser films are enhanced by the refurbished glow, especially “A Night in Casablanca.” Both are perfect gifts for matriculating freshmen.

Mr. Giddins’s column appears alternate Tuesdays in the New York Sun.