A young woman of good family -- actually, very good family, the Spencers -- wins the catch of her generation of English Roses, the heir to the throne. She proves to be admirably fitted for the princess biz: a looker, whose looks improve as she settles into the job; tolerant (for the most part) of the tedium of official life; and possessed of a genuine concern for unfortunates in general and children in particular.

There are drawbacks. She has little in common with her husband and apparently lacks royalty's centuries-old blind eye to extramarital affection. This particular complication is hinted at in one of the exhibition's narrative labels, which mentions that as Charles starts to court Diana he takes her, one evening, to dinner with his friends, the Parker-Bowles. The world knows what that means.

What a story! Of course, we all ate it up, and who among us wasn't taken aback when the saga reached its tragic end? There are elements here for any student of popular culture, for psychologists interested in the mysterious appeal of royalty to commoners everywhere, for all of us who just wonder how people live in those big old houses with all those servants.

The last question is answered disarmingly with home movies from Diana's childhood and a selection of toys from the nursery she shared with her siblings. Very nice toys, yes, but not art.

Visual art is sparingly represented. An unfinished work by Sir Godfrey Kneller, portraitist to the great through multiple 17th- and 18th-century reigns, shows Sarah, Duchess of Marlborough, whose Spencer connection actually was as mother-in-law. However, she gave the family her substantial art collection and a huge estate, so she qualifies as a Spencer-enhancer. A rather wooden Gainsborough shows an 18th-century Spencer woman as a child. Gainsborough could paint children admirably -- see "Edward and William Tomkinson" at the Taft Museum -- but this work came from an off day.

The real art in the exhibition -- excepting some tools of the royalty trade: tiaras, coronets, jewels in general -- is in the clothing. The princess wore clothes beautifully and perhaps could have been a supermodel if fate had not dealt her Charles. The wedding dress, which seems to me a touch fussy with its 25-foot train and bows and ruffles, has a room of its own.

The final gallery of the exhibition displays Diana's working clothes -- the day and evening dresses she wore in public. It is in fact a mini-survey of fashion in the late 20th century and is pleasantly enlightened by photographs of Diana in the actual clothing we see on the mannequins.

In other galleries we find Diana's childhood passport, a whole library of books made up of letters of condolence at her death, handwritten lyrics for the Elton John/Bernie Taupin work played at her funeral and other memorabilia from a short but heavily documented life.

This same exhibition is on view at the Spencer family estate, Althorp, during the summer months but is free to travel the rest of the year. The Dayton showing winds up its current U.S. tour. The whole thing has a slightly hasty look about it. There are minor grammatical errors in the expository labels and a photograph that seems to be of the island where Diana is buried at Althorp appears twice in huge blowups and once as a detail but any identification is so discreet that I missed it.

Diana was fantastically good at her major assignment, aside from producing "an heir and a spare." This was to add a human, appealing face to the British monarchy. When she died, the world caught its breath. As it happens, my son lives in London and was a near neighbor, on a substantially less upscale street, to Diana in Kensington Palace. In the hushed period between her death and the funeral, he called to say how strange it all was. "Every other person on the street is carrying flowers to Kensington Park. They have teddy bears, all sorts of things. They're making personal memorials to her."

He went on to tell me of a restaurant that Diana was known to frequent. Late in the evening there might be a flurry of laughter and motion as Diana and friends went up a staircase to a private room. My son, passing there one afternoon, saw the proprietor standing at the door. "The butterfly has flown," said the man.

This is an exhibition about the butterfly who has flown. It is compelling for many reasons, some of them the wrong reasons, but its meaning is sociological, not artistic. Diana, A Celebration is being circulated by Arts and Exhibitions International, a company whose track record suggests the proposition that the blockbuster is all and bringing people through the doors in the thousands is the sole aim of art museums.

I don't think so. As art museums become so all-fired friendly, they are likely to lose the art. Come on, guys. Could we try a shot of elitism, just for the fun of it? Grade: C