That film confronted the eternal verities of diminished expectations, mortality, and bowling; the new one takes on true love, the plight of the handicapped, and the perennial inconvenience of taking a leak. This last is the downfall of Ted Stroehmann (Ben Stiller, the master of painful phallic comedy since Flirting with Disaster), whose problem, unlike Swift's, is not so much that he is without skin as that he has too much of it, particularly in places where it comes in contact with sharp metal objects.

An especially painful instance occurs when he arrives to take Mary (Cameron Diaz), the most beautiful girl in Cumberland, Rhode Island, to the high-school prom. After the intervention of Mary's stepfather (Keith David, African-American and uncommented on), her mother (Markie Post), the police, and the fire department, Ted is hospitalized, and his one shot at true love seems lost forever. Mary and her family move to Florida, and he's left 13 years later baring his broken heart to an indifferent psychiatrist.

Like Mr. Jealousy and The Truman Show, Mary is partly about obsessive love, here a nice term for stalking. Spurred on by his friend Dom (Chris Elliott), Ted hires private detective Pat Healy to track Mary down. Played by Diaz's real-life squeeze, Matt Dillon, who sports leftover wardrobe from Kingpin and a truculent, clipped moustache that looks like a third eyebrow, Healy is a crass and unprincipled Bud man (this is a film in which even the product placements elicit a laugh), but his soul too is touched by Mary's blithe beauty. Armed with surveillance equipment, he concocts a new identity for himself designed to win her heart.

The stalker aspect alone is bound to raise questions of political correctness in this movie. Then there are such outrageous sequences as the spectacle of Mary's disabled friend Tucker (Lee Evans) twitching and skipping on his crutches in an effort to pick up a dropped set of keys. (People at the screening I attended, myself included, watched the spectacle in frozen horror, not laughing until Mary slammed the door on her determined, stricken friend -- hypocrites, all of us.) The Farrellys have the gift for generating laughter from discomfort and vice versa, an insight commonly misconstrued as bad taste.

That's the situation in a key scene where Mary's mentally retarded brother, Warren (W. Earl Brown), wearing red earmuffs and wandering in search of his baseball, is lured into a cruel trick that ends in his being pummeled by a meat-headed jock. Suddenly it's not funny, and you're glad when a quixotic Ted tries to intervene. Unlike most films that sentimentalize handicapped people, however, Mary thereafter feels free to have fun with Warren, and we in the audience, in theory at least, feel free to laugh.

The excruciating balance between comedy and cruelty worked out in this scene is at the heart of the movie, and it's Ted's ability to walk the line between meanness and mawkishness that makes him the most appealing of Mary's suitors. His attempted rescue of Warren is what wins Mary's love -- that and Stiller's endearing performance. He's one of the more underrated comedians around, bringing to the role some of the childlike innocence of Harry Langdon and the stolid unperturbability of Buster Keaton (and though he doesn't have the physical skills of these masters, he gives a good account of himself in a scene with a tiny, amphetamine-crazed dog).

Then there's Diaz, the closest thing to a human sunbeam on the screen. Whereas Stiller's Ted is velcro when it comes to dodging the various mischances and wayward bodily fluids that besiege him, Mary radiantly glides above it all; beneath tresses cowlicked with an inappropriate substance resembling hair gel, her grin nonetheless sails over the hilarity. There's something about Mary that would convince the curmudgeonly Swift of "To Celia" fame that humanity's beauty transcends its grossness and frailty.