Guides at Boston's Gardner Museum sometimes point out the second-floor landing overlooking the atrium, from which the legendary Nellie Melba serenaded Isabella Stewart Gardner and her guests below, one night in 1905. On this same spot, decades later, I posed for my college yearbook photo. This they never mention.

All right, so I'm no Nellie Melba.

But I probably visited Mrs. Gardner's more often. Having attended Simmons College right next door, between classes I coveted her Renaissance palazzo on the Boston Fens. It was my dream house, and Mrs. Gardner just the sort an unreconstructed English major and budding feminist, circa 1972, would have admired -- a woman for whom Paderewski had played and Pavlova had danced, a woman painted by John Singer Sargent, advised by Bernard Berenson and attended by Henry James, Henry Adams, James McNeill Whistler and Julia Ward Howe, among others.

In turn-of-the-century Boston, the celebrated Mrs. Gardner -- art collector, patroness of the arts and social activist -- neatly straddled Brahmin and Bohemian society. She was much admired for her originality and legendary charm, much envied and speculated about in newspaper stories that border on the apocryphal.

And how she carried on! There was that gloveless, V-necked Sargent portrait that scandalized Victorian society; the rumors of the widow's affairs with the younger artist, or the famous art dealer; and the other eccentricities -- her professed Buddhism in a Protestant Boston, her habit of borrowing lion cubs from the zoo and exercising them in the Public Gardens. And there was that house she was building -- that Eyetalian palace -- for herself and her paintings.

That notion -- to build first an art collection, then a museum to house it -- was also occurring to Henry Clay Frick in New York, Henry Walters in Baltimore and, 20 years later, to Albert Barnes in Philadelphia. Their "vanity," "personal" or "boutique" museums, while celebrations of self, of private vision (or obsession), are also monuments to extraordinary largess. Gardner, Frick, Walters and Barnes all bequeathed millions of dollars in art to their fellow citizens.

Vanity museums, with their remarkable collections due to the energies of one person, are often subjected to their creators' quirky behests. The Gardner and the Barnes, for example, are endowed "as is." The art cannot even be rearranged, but must remain as originally hung by the collector; no new acquisitions can be made. The budget goes to conservation. In New York and Baltimore, however, Frick and Walters eschewed the idea of art as mausoleum. The collections have grown, the facilities are embellished and restored.

Collected in the era of the ubiquitous Bernard Berenson and Joseph Duveen, the Gardner, Frick and Walters museums all bear the stamp of these infamous dealers. All are housed in Renaissance revival buildings, the style of the day, built as both museums and private homes.

Of all the vanity museums, it is Isabella Stewart Gardner's former residence on the Fens that typically fuels the most fanatical kind of devotion -- the museum's visitors must surely be among the most proprietary anywhere. They attend the memorial service held yearly on the anniversary of her death (April 14), wish they had known her, spend hours staring dreamily into the courtyard. They took it personally when the museum was burglarized last March, in what some call the biggest art heist in history, with 13 paintings valued at more than $200 million stolen, including three Rembrandts (among them a rare seascape), several Degas and a Vermeer, one of only a few dozen in the world.

A few months after the theft, I revisited the Gardner with apprehension. Was I imagining it, or was there a more somber, less tranquil mood here? The doors overlooking the balcony on the second and third floors, which had always been open in the past, were now closed, denying visitors the pleasure of standing and contemplating the breathtaking four-story indoor court below.

On the walls where the stolen paintings had hung were simply notices -- "Stolen March 18, 1990." But with plenty of other paintings still hanging on the beautifully paneled walls, there were no obvious holes.

I returned several times in the next few days, and after the initial shock, was reassured that though the collection might be diminished, the spirit of the place had not been. After all, the palace itself is a work of art. "Fenway Court," as it was known then, was constructed from bits and pieces of old Italian palazzi -- arches, staircases, fountains and balconies. With its four-story indoor court, where flowers bloom year-round, the setting almost eclipses the art.

Though she hired an architect, the widow of Jack Gardner (a clipper ship and railroad man and scion of an old Boston family) really conceived this Renaissance palazzo turned inside out. Its facade in the round, with eight balconies that once looked out on the Grand Canal in Venice (thought to be salvaged from a Ca D'Oro facelift), encircles the glassed-in court. But Fenway Court was inspired by another Venetian palace, Palazzo Barbaro, which she rented for eight summers.

Gardner moved in by Christmas of 1901, and Fenway Court opened to the public in 1903 to general acclaim. The philosopher William James wrote on the morning after the official opening that "the aesthetic perfection of all things ... seemed to have a peculiar effect on the company, making them quiet and docile and self-forgetful ... as if they had become as children."

There is no denying that "peculiar effect" still. Visitors sit dreamily on the stone walls of the cloisters, listening to the fountain trickle, breathing the sweet, dewy hothouse air and gazing at the courtyard, with its second-century Roman mosaic floor and throne. They are lost in Gardner's Victorian version of the Renaissance, and in delicious serenity. (Photo opps on the Nellie Melba balcony, however, are no longer permitted by the guards.)

The museum's own security people, more obviously on guard than in my college days, have their hands full of such admirers -- especially on Wednesdays, the free day, when it can seem as crowded as Piazza San Marco in July. Better to go another day, pay the $5 admission fee and savor three floors of old masters, sculpture, manuscripts, furniture, textiles and ceramics collected by the Gardners together, then by the widow alone after her husband's death in 1898.

With Isabella Gardner in attendance, the public was admitted during her lifetime for two weeks at Thanksgiving, and two weeks at Easter -- 200 people a day at $1 a head. On the first floor they saw the courtyard and the adjacent Spanish Cloister, originally a two-story music room -- the top half of which Gardner later converted into the current music room to display her 16th-century Flemish tapestries. Here members of the Boston Symphony serenaded the guests on opening night at the palace, with Gardner greeting guests from the balcony, wearing her famous diamond antennae (early "killer bee").

On the two floors of public rooms above, Mrs. Gardner entertained (her living quarters were a private apartment on the fourth floor). Room after room evokes a different era -- some richly paneled, covered in hand-tooled and gilded leather, or hung with damask, with floors of wood or uneven stone. The ballroom-sized Tapestry Room, or Music Room, doubled as Gardner's formal dining room. Today, public concerts are held there three times a week.

The somber Dutch Room was the scene of the recent theft. The three Rembrandts and a Vermeer that once hung here are gone; a Rubens, two Holbeins, and many others remain. In a painting of Queen Mary, the queen wears the substantial Pelegrina pearl, now owned by Elizabeth Taylor.

Upstairs are the Veronese Room and the Titian Room, which contains the most valuable painting in the collection, Titian's "Rape of Europa." Also on this floor is the chapel, with its 13th-century stained-glass windows, where the April memorial service is held every year.

A more urbane memorial -- Sargent's famous portrait of Gardner at age 48 -- hangs in the Gothic Room next door, which Sargent used as a studio during the winter of 1903. With its pearl necklace draped around her middle, showing off a wasp waist, a hint of decolletage and shockingly bare arms, the painting outraged Victorian society. Fueling the controversy was the way Sargent had posed his patroness before one of her tapestries, with a kind of halo around her head in the manner of a medieval saint.

While Isabella Gardner was periodically deemed "in" and "out" by Boston society, she was still indisputably a part of it. Though he lived on the Main Line, Albert C. Barnes of Merion Station, Pa., was always an outsider. The irascible creator of the Barnes Foundation waged vitriolic letter-writing campaigns in the local press, against real and imagined enemies.

The city appreciated neither him nor his art. Ill feelings between Barnes and the public and press supposedly were cemented when he showed his collection at the Philadelphia Academy of Art, to the scorn of the art establishment, which had not yet come to appreciate the new European wave. From this time on he resolved to keep his art to himself. Only those Barnes personally invited could see his paintings.

Barnes died at 79 in 1951. Since 1961, to ensure its tax-exempt status as an educational institution, the foundation has been required to admit the public. From September to June, it is open on weekends.

As at the Gardner, Barnes's spirit still prevails here -- but the atmosphere is not exactly cordial. When I visited, I felt more like an uninvited guest. A sign warns "No spike heels, smoking, eating, photos, lecturing, or any activities that disturb other visitors." There are no guidebooks to the museum, only the foundation's publications -- journals and weighty tomes on the art, many written by Barnes himself. Color reproductions of the works on display are strictly forbidden by Barnes's will: You cannot buy so much as a postcard here.

My questions about "the Doctor" and his collection were largely evaded. The staff talked about him in hushed whispers, as if they still expected him to come through the door any minute.

You begin to wonder why you came. Until you see the art -- more than 1,000 paintings, mostly impressionist and modern art, with some old masters. The numbers are staggering: 200 Renoirs, 100 Cezannes, 30 early Picassos, 60-odd Matisses (including a Matisse mural, "The Dance," commissioned by Barnes).

The 23 rooms of paintings are exactly as Barnes left them. Paintings overwhelm the walls -- some hung almost perversely high -- arranged by Barnes himself to illustrate the theories of art education practiced and taught at the foundation. They compose what he called "wall pictures," with each wall and its grouping of paintings making some aesthetic point. The effect is dizzying. You come out exhausted, wondering about the man who assembled such an extraordinary collection, at a time before modern art became a hot commodity.

Barnes made a fast fortune with Argyrol, the silver nitrate antiseptic put in newborn babies' eyes, then devoted the rest of his life to collecting modern canvases, acting as his own agent. He collected Renoir's beautiful paintings of beautiful people, Cezanne's apples, Modigliani's and Seurat's women -- installing them in a mansion designed by Paul Philippe Cret, who designed the Folger Shakespeare Library. According to one source, he discovered Soutine, reportedly buying up 50 paintings at $50 a crack; championed the American artist Glackens; and was an early fan of Modigliani.

When he was not on buying trips to Europe, Barnes ran the foundation, which teaches art education based on Thomas Dewey's principles of the scientific method, or what Barnes called the "objective method." His was an egalitarian approach -- he believed that art was not for dilettantes, or just the elite, and that anyone, regardless of education, could appreciate and understand it with the proper guidance -- his.

Henry Frick made his fortune in coke in Pittsburgh, establishing himself as a major collector from 1905-13. When the young Frick applied for a business loan in the early '20s, the loan officer noted that Frick "may be a little too enthusiastic about pictures but not enough to hurt." This passion for art profited New York City, where the captain of industry settled. Inspired by a visit to the Wallace Collection in London, Frick bequeathed his splendid collection to New York -- including Hogarth, Reynolds, Titian, Holbein, Gainsborough, Whistler, Van Dyck and Franz Hals. Frick seemed to favor portraits, and among them, appropriately, is his own -- a handsome picture of a white-haired and bearded Frick -- a strong, beneficent face.

Unlike Gardner and Barnes, who were outspoken artists' advocates, Frick went about his collecting in a much more quiet way. In the biography "Henry Clay Frick, the Man," published by the collection, there is little mention of his activities as an art collector until virtually the end, with a chapter entitled "An Art Collector," which merely lists the works "selected and purchased by Frick personally between 1888 and 1919." And yet he is best known for his art collection.

After the death of Frick's wife, the Frick Collection opened to the public in 1935. Today, locals and tourists, American and foreign, wander among the sculpture, furniture, porcelain, enamels, rugs, silver, books, drawings and prints -- a diverse collection of late-13th- to late-19th-century works. Paintings here are not shown by school or period, which gives the feeling more of a private home than a museum.

The atmosphere here is low-key, without the sense of an agenda imposed upon the viewer, as at the Barnes Foundation. Guard ropes are minimal, to retain the "domestic atmosphere," according to the collection's brochure. As a result, children under 10 are not admitted, and those under 16 only with an adult.

Like Frick, Henry Walters of Baltimore left his art collection to the public -- more than 22,000 works that span 5,000 years of art. His father, William, the railroad magnate, had collected the 19th-century art and Oriental porcelain, while son Henry took nothing less than the whole history of art as his province.

Like Isabella Gardner in Boston, Henry Walters was not shy about collecting, and he knew what he liked. He caused something of a scandal with his purchase in 1886 of an 18th-century Chinese peach bloom vase, now considered priceless, for $18,000. Rumors also abounded about his personal life. He lived in New York with his friend Pembroke Jones, a wealthy rice planter, and Jones's wife, Sarah, and the three traveled extensively together.

In 1902, the younger Walters bought the entire contents of a Roman palace -- more than 1,500 works, including antiquities, sculpture, decorative arts and late medieval, Renaissance and Baroque paintings. He chartered a ship to transport the collection to Baltimore and had a museum built to house it, modeled after the Palazzo Balbi, a Baroque palace in Genoa. The Walters Art Gallery opened in 1934, three years after his death, though it had previously been opened to the public on a limited basis.

One could happily spend a day here among the Egyptian bronzes, medieval manuscripts, 18th-century Sevres -- and the little treasures like a Faberge parosol handle and a Samovar-shaped cigarette lighter, and finely wrought 16th-century Venetian wedding rings. In the two-story picture galleries, visitors are drawn from one room to the next by delights like a Hugo van der Goes -- one of only 15 works left by the Flemish master -- and great masters like Brueghel and Bellini (Giovanni), El Greco, Raphael and Veronese. Walters' expansive collection also includes intriguing works by lesser-known artists, like the compelling "Mourning Woman" by Ercole De Roberti.

There are few reminders of Walters the man among the masterpieces, perhaps because this was not a private home. But whatever the reason, you think less about Walters here (and more about the art) than you do about Frick at the Frick, Barnes at the Barnes and Gardner at the Gardner. In that sense, the Walters may be the least vain of the vanity museums, the most successful in celebrating the art, rather than the ego, of the collector.

Barbara Ann Curcio is a Washington writer.

WAYS & MEANS Barnes Foundation, 300 N. Latches Lane, Merion Station, Pa. 19066, 215-667-0290. Open September through June, Fridays and Saturdays 9:30 a.m. to 4:30 p.m., Sundays 1 to 4:30 p.m. Reservations required for groups of 10 or more. Free admission.

Isabella Stewart Gardner Museum, 280 The Fenway, Boston, Mass. 02115, 617-566-1401. Open Tuesdays noon to 6:30 p.m. (noon to 5 p.m. during July and August); Wednesdays through Sundays noon to 5 p.m. Admission $5; Wednesdays free.

Frick Collection, 1 E. 70th St., New York, N.Y. 10021, 212-288-0700. Open Tuesday through Saturday 10 a.m. to 6 p.m., Sundays 1 to 6 p.m. Admission $3.

Walters Art Gallery,600 N. Charles St., Baltimore, Md. 21201, 301-547-9000. Open Tuesday through Sunday 11 a.m. to 5 p.m. Admission $3; Wednesdays free. -- Barbara Ann Curcio