MOST ART MUSEUM curators tend habitually--often compulsively -- to frequent other museums. Any pretext will do. Major exhibitions on home turf must be seen, for obvious reasons. Traveling automatically means intensive museum-going. Obscure institutions hold the fascination of discovery, and the great museums can never be seen too much. The only museum-free vacations are the ones taken in places where there aren't any art museums.

All this is by way of saying that I, who am among the most driven of exhibition haunters, presume to know a superb exhibition when I see it. And though I will go to considerable lengths to see an important show, I am not one of those for whom the ardors of the quest sweeten the reward. I can appreciate a wonderful art exhibition visiting my own museum (or even self-curated) as much as one in Antwerp or Tokyo or Sydney.

This fall season, if I lived in any of those places, I would have no hesitation whatever about coming to Washington, D.C., merely to see a modestly scaled exhibition of Renaissance drawings from the Ambrosiana collection in Milan. It hangs now in the National Gallery of Art, and by my lights it is as good as these things get. This show not only presents objects that have virtually never been on public view outside their ancient home institution, but presents these fragile if pristinely preserved objects in optimal conditions.

Here are 87 drawings, primarily 14th- to 17th-century Italian leaves, with a (strangely upstaged) smattering of northern pieces -- Du rers and one Holbein, one Bruegel -- juxtaposed perfectly, selected with the most authentically grounded feeling and imagination, hung with impeccable taste and intelligence.

What is so astonishing about this show is its consistently superlative level of not exactly quality, but quickness. These essentially provincial drawings palpitate with living spirit. Intimations of what can only be called genius are conveyed in the hands of often "minor" masters, and usually minor-scaled works. The only stellar names are those of Leonardo, Pisanello, Giulio Romano, Sebastiano del Piombo, Vasari, Pordenone, Albrecht Du rer, Pieter Bruegel the Elder, Hans Holbein the Elder. These are beautifully represented. But many of the greatest pieces are by artists whose names can mean little or nothing to anyone but the most specialized scholars. It is in a sense an insider's show, if by this one means an exhibition unconcerned with the box-office appeal of the familiar names.

But in another sense, it is as accessible, as broadly appealing, as any array of artworks I have ever seen -- in its fresh pacing and in the legibility of its subjects. These range from a single breathtaking classical drapery study, to a book-illustration Nativity scene, to an awesomely beatific head of Saint Barbara. There are studies of animals, studies of vegetation, narrative scenes of familiar and esoteric Christian miracles, three or four portraits. And there are angels. It is the angels that move one's innermost being -- the two radiant, gossamer Bernardino Luini heavenly ghosts and the Il Morazzone depiction of a soul's winged rescue from purgatory. These drawings aspire to an ecstatic state. They are not the most polished or sophisticated of Renaissance objects, yet they are perfectly expressive of something transcendent, something beyond sophistry.

This show challenges my conviction that the best exhibitions are lonely efforts. It is the result of collaboration between several scholars -- primarily Robert Coleman and Louis Jordan of Notre Dame University, Diane DeGrazia of the National Gallery, Giulio Bora of the Universita degli Studi di Milano, Bert W. Meijer of Florence and Alessandro Nova of Milan. It resulted from months of negotiation and compromises and the ever-present problem of the Italian government's bureaucratic hurdles when it comes to borrowing artworks. Perhaps it bespeaks the potential of dedicated minds, forced to act in accordance, to produce a cohesive body of images complex enough to assuage our own individual appetites for subtle acts of discrimination.

This delicate exhibition is at the National Gallery until Oct. 7. Its component works are timeless and consoling and achingly masterful. Above all, it is a gathering of sublime and humble works of art whose unfamiliarity bestows upon them an incomparable attribute, that of discovery, which is all that is denied to the deservedly beloved famous masterpieces.