The films of the great silent-film star Harold Lloyd inspire two kinds of laughter.

Mostly there is a mild, knowing laughter, a laughter that acknowledges, across the space of eight decades, that this must have been very funny when it was new. Then there are the laughs that take you by surprise, the spontaneous, didn't-see-that-coming sort of laughter that proves that Lloyd's comedy, at its best, is as fresh and as shocking as anything produced today.

Leonard Maltin, who provides commentary for a new, three-volume, seven-DVD Harold Lloyd Comedy Collection, writes, "Not only does his comedy play to any audience of any age in any country, but it's just as funny today as it was in the 1920s."

That's not entirely true. The films of Lloyd are very much steeped in both the charm and ugliness of their era, the 1920s, when the entire middle class seemed to be in high school -- caught up in a whirl of silly romance, benign one-upmanship, petty ambition and generally fun-loving high jinks.

But scan his movies intently for a sign of the Other, people of different races, outsiders, and you realize that these films epitomize the last, regnant, unalloyed era of Whiteness. A Chinese man who wanders into the 1928 "Speedy" is a caricature; a Jew who sells Lloyd jewelry in the 1923 "Safety Last!" is a penny-pinching stereotype; black characters, always incidental, are generally ridiculous, vaudeville reductions.

So the films aren't universal, but very particular to what might be called the Golden Age of the White Man, which is also essential to understanding the charm of Lloyd's character. Unlike Buster Keaton or Charlie Chaplin, the Lloyd character -- a young man with a blazingly pale face, set off by a shock of dark hair and often a dark suit -- is utterly at home in his world. He may be insecure, or poor, or reduced by love to ridiculousness, but he inhabits his world as if he owns it.

Yes, the world is modernizing, getting faster, sometimes dangerous, but Lloyd is a descendant of Huck Finn, Tom Sawyer and all the earnest, androgynous, ambitious adolescents of Horatio Alger's novels. He is the essence of pluck, the virtue that privileged men always recommend to the less fortunate, unaware that pluck and opportunity don't go hand in hand. Pluck works for the right people, the ones for whom the rules have been written to ensure a happy ending.

So when a real laugh breaks through the fantasy world of Lloyd's films, it pierces more than just the polished, mesmerizing veneer of his supremely well-made comedies. It connects us, via a comedic thread that stretches back through the comic operas of Rossini to the rustics of Shakespeare, to a manic and redemptive creativity -- often most pronounced in artists working with a new form, or a form that they are completely remaking. Among the many pleasures of watching Lloyd at work is the sense that he is not only a master of the minutiae of film mechanics, but he's also pushing the limits of the new medium's basic narrative coherence. And it's when he pushes those limits that we laugh the hardest.

In "Ask Father," a 13-minute short from 1919, the gag is all simplicity: To marry the girl, the boy must ask the father's permission, but the father is consumed with business, and imperious when it comes to distraction. Lloyd makes repeated efforts to gain access to the sanctum sanctorum of the man's inner office, and is repeatedly sent packing by the front-office men. A kindly secretary takes pity on him enough to lay out a cushion for his many crash landings into the corridor. She knows, before he knows, that he's about to go flying again, a clever acknowledgment of the basic truth of slapstick: It may seem to be woven from accidents and coincidence and preposterous turns of fate, but the outcome is always the same.

But then Lloyd makes another attempt on the father, this time dressed from head to toe in a suit of armor, breastplate, greaves, gauntlets and visor. It is a pure non sequitur, something that the early David Letterman or Monty Python might have thought of.

One particularly pleasurable danger of comedy is that something will go off course, some word, misheard, will send a character down the wrong path, perhaps without recourse. Lloyd may be making a subtle comment on the idea that the boy-fights-for-girl setup is one of the oldest in the book, hence the throwback to the days of chivalry. But more likely, he's just thrown in a visual wild card to see whether it will derail the smooth choreographic process of the film. It doesn't, but it comes close, and we laugh without inhibition or condescension.

There are moments like these throughout the 15 feature films and 13 shorts collected on these DVDs. In the 1924 "Girl Shy," Lloyd imagines various romantic conquests, recording his fantasies in a manuscript, the publication of which he hopes will make his fortune and secure for him a real girl. In one chapter he seduces "the Flapper," a modern woman (she smokes!), with "my caveman methods." Few men were physically or temperamentally less suited to playing the "caveman" than the character created by Lloyd. The results are hysterical.

Another Lloydian moment comes at the end of "From Hand to Mouth," a 1919 short, when he celebrates victory -- it's always the same, he beats the clock and gets the girl -- by eating a breakfast of pancakes with a pair of scissors.

Lloyd was born in Nebraska in 1893, and he retained throughout his career the definite impress of wholesome Midwestern good health. His early forays into film were made in the shadow of Chaplin, but he eventually broke free of the "tramp" to develop his famous "glasses" character, a boyish man with Harry Potter-style round glasses. As an actor, he didn't go for range; rather, he worked in what might be called the sitcom mold, refining a basic archetypal character through all the possible variations. Although his films have been eclipsed over the years by those of Chaplin and Keaton, he was every bit an equal member of the club of early comedy greats.

Lloyd had both an acrobat's physical gifts and a magician's small-muscle control. His most iconic scene, hanging from a clock many floors above the ground in "Safety Last!," demonstrated his sheer strength and flexibility. But he was good at sleight of hand as well.

Just as impressive as the heart-stopping heights of what became known as "daredevil comedy" are the equally numerous moments when he does something with a glass or a fork or a vase in the smaller confines of indoor comedy. As he became more accomplished and more popular, he eventually set himself up as his own producer. Eventually he was one of the richest men in Hollywood.

Lloyd's comedy wasn't endlessly inventive. Patterns and conventions emerge. Early American film gravitated to motion just as naturally as photography gravitated to portraiture in its early days, and the basic setup of a Lloyd flick requires something to set the clock running, and a big prize for winning the high-stakes race. Money and a girl generally fill the latter requirement. The former, the need for speed -- for a car, bus and buggy chase -- was where the real creativity came in.

With that basic architecture, the films play out rather like operatic comedies, with highly developed, multi-part gags substituting for arias and coming in a handful of basic varieties. There are the accidental thefts, when Lloyd steals (and gets nabbed) without intending to (in one case, a crab falls into his coat pocket and pinches things for him). There are taunts to authority (cops with batons) that are based on small but crucial mistaken assumptions. There are the things that he must wear or carry that turn the world into a threatening obstacle course. And then there is the category of the "fortuitous," for which the film critic Siegfried Kracauer singled him out for praise, a category that includes things like a construction beam sliding accidentally through a window and under the seat of an office chair so that it carries an innocent secretary from the security of his desk to a swinging perch hundreds of feet off the ground.

By the 1930s, with the advent of the talkies, Lloyd's career was winding down. The accepted theory involves age -- it was getting harder to play the generic "boy" character -- and the advent of the Depression, which turned the general audience to pessimism.

But watch the 1930 talkie "Feet First," and you realize that it wasn't just crow's-feet or the country's souring mood that brought the genius to an end; it was the change of pace, a loss of the manic internal tempo that defined his earlier work.

In his spoken features Lloyd sounds just as you might expect: polite, plucky, confident but not overbearing. But when he repeats his daredevil comedy in the sound age, you hear the grunts and gasps and heavy breathing. The purely visual music of the high-flying dance is gone.

In part it's a literal loss of music. Robert Israel's scores for Lloyd's movies, included in this collection, are magnificent, and they clarify and underscore the basic rhythm of the films. It's a loss not to have them in "Feet First," but it's not the only loss. The new film genera require more plodding, more setup, more chitchat, more space between gags. You know it's still a Harold Lloyd film, but it feels like it's on depressants.

One can't help but think of Rossini, the composer who injected speed and acceleration into operatic comedy as surely as Lloyd injected it into the movie comedy. Rossini's great comedies are always built to a magnificent stretto, a quickening of the pace, a building of tension, that takes place over ridiculously long arches. He pulls back from the madcap only to gather strength for a new assault on absurdity.

So too Lloyd at his best. It's a reckless, prodigal form of entertainment, and a dizzying one. It can't be sustained for long -- a dozen or so forays, a decade perhaps -- before it begins to get dated. Lloyd sustained it for 10 years -- and like Rossini, he retired at the right moment, lived well, and is remembered fondly in perpetuity.

The Lloyd aesthetic would live on, here and there, in Bugs Bunny cartoons and Jackie Chan films. But it was a chapter that had to have an end, and for Lloyd it was closing by 1930. While it lasted, the results were spectacular. Lloyd's world of earnest college boys, ambitious young salesclerks and moon-faced lovers was a claustrophobic one, but shafts of light and laughter always broke through and are still captivating today.

Harold Lloyd showed a talent for physical comedy in 1923's "Safety Last!," when he dangled from a clock face.

Silent-movie star Harold Lloyd, in "The Freshman," left, and "Doctor Jack," above, played a simple character in his many films: a wide-eyed and plucky young man who had to use his creativity to get out of a sticky situation.