High on a craggy hill somewhere in the Latium countryside near Rome, the ruins of an ancient castle once stood, keeping ghostly vigil over a tumbling gorge below. It was ancient even when Netherlandish artist Bartholomeus Breenbergh drew it sometime in the 1620s. The walls of its once formidable, lofty keep were crumbling, and vegetation had taken root between the stones. No babble of courtiers, no bustle of soldiers echoed in its cavernous chambers. No faces peered from its windows or bowmen's slits.

This small but haunting pen-and-wash drawing is but one in an exhibit of 86 Old Master drawings from the collection of the National Gallery of Scotland in Edinburgh that opens here today at the National Gallery of Art's East Building. Breenbergh may not be a household name, but you'll find works here by Raphael, Rubens, Fragonard, Rembrandt, Tiepolo, Van Dyck, Poussin and many other better known masters. The drawings were selected by Hugh Macandrew, keeper of prints and drawings at the National Gallery of Scotland, and Andrew Robison, senior curator at the National Gallery. And although for various curatorial and legal reasons there are no British or German drawings in this show, the breadth and scope of the works included make it clear that the National Gallery of Scotland's is a magnificent collection indeed.

Contemporary artists have largely forgotten the exquisite charm, intimacy and unique grandeur of fine drawings: the way they reveal the very bones of an artist's style and technique, and the methods by which he arrived at his formal, painted compositions. More, a great drawing can convey an immediacy and truth that a finished painting rarely achieves. But perceptions of the relative merits of different graphic art forms have changed over the centuries. Fine pen-and-ink studies such as Breenbergh's castle, or Roelant Savery's evocative and detailed "An Inn on the Outskirts of Prague" (c. 1603-1605), Jan Bruegel the Elder's "Landscape With Two Peasants and Castle" (c. 1605-1610) or Salvator Rosa's "Studies of Fighting Men" (1652) were once collected by connoisseurs and preserved in folios as finished works of fine art in their own right. That's why they've survived to delight us today.

A good many of these drawings, by better and lesser-known masters, are stunning examples of draftsmanship. They speak eloquently to the powers of observation and technical prowess of the artists who created them. The National Gallery of Scotland's recently acquired red chalk study of "A Nude Woman Kneeling with Her Left Arm Raised" by Raphael (c. 1518) is a case in point. If anything is needed to vindicate the magical beauty drawing is capable of attaining -- a quality for which artists strove for many centuries -- this will certainly do. Only a handful of the greatest artists have had such command of rendering the human figure -- Michelangelo, Watteau, Leonardo, Caravaggio, perhaps Rembrandt. And it's telling that in this post-photographic age of video, laser and holographic images, studies such as this fragile, tiny chalk image retain the passive power to inspire awe.

The exhibit is full of unexpected treasures. You might, for example, have thought French classicist Nicolas Poussin to have been a rather pedantic and stilted stylist -- and with some justification. But take a look at his lovely little study for the salon composition "A Dance to the Music of Time" (c. 1640). Here the artist worked freely with brown ink in a manner that invites comparison with some of Cezanne's and Matisse's gestural figure studies. The composition is vibrant with movement, each of the dancing female figures masterfully limned with a few sure strokes of pen or brush. In short, there is to this study a whimsy and vigor you'd scarcely have associated with Poussin had you been familiar only with his finished paintings.

Here, too, there is a superb wash study by Piranesi for one of his "Imaginary Prison" etchings of the 1750s. The sheet is remarkably well preserved -- so well, in fact, that it looks as though it might have been executed only last week. And the artist's technique is startling. Gestural, evocative and vast in scope, if not in physical size, there is not a brush stroke out of place, not a tone or shading of wash imprecise or alterable in the imagination. It is an image, I would guess, that Piranesi completed in a very few minutes, merely wishing to commit to paper a concept for or revision of one of the famous series of etchings of dungeons that occupied him for many years. Yet as a work apart, it's every bit as powerful as one of the finished prints.

The range of subjects depicted by the various artists represented in this exhibit is a delight in itself. Not all of them confined themselves to grand Biblical or mythological themes, fighting scenes or pastoral landscapes. There are, for example, such charming works as Jacques de Gheyn the Younger's "Studies of a Frog," and a marvelous, quick little ink wash sketch of a "Man and Woman Seated at a Table" by Rembrandt's student Ferdinand Bol (c. 1640-1645). The master's influence is perfectly evident in the sure, effortless brushwork that describes the play of light and shadow about the tiny chamber in which the couple sit chatting in confidence, their shadows looming against the corner behind them.

Even the drawings here by Sir Peter Paul Rubens are uncharacteristically prosaic -- and doubly compelling for all that. His two quick ink-and-chalk sketches of peasant women harvesting show the flamboyant Flemish master at his most direct, observant of the commonplace world about him. And, by contrast, there is a magnificent drawing by the master Italian printmaker Pietro Testa (1612-1650).

This highly finished composition, rendered in pen and brown ink over a faint black chalk sketch and reference grid, depicts the grandiose theme from Virgil's "Aeneid" of "Venus Giving Arms to Aeneas." This is a classic example of the drawing as finished work of art. At roughly 12 1/2 by 16 1/2 inches, it's larger than most of the works in the exhibit, and may have been intended for direct transfer to a copper plate for engraving. In the center of the tightly constructed composition, the voluptuous goddess of love, assisted by winged putti, hands her warrior son the armor Vulcan made for him. It's worth lingering over the details: every leaf of the trees, the Tuscan landscape in the background, the river god slumped humbly in the foreground. Each element of the composition is executed with the precision of a silversmith.

When you've examined "Venus Giving Arms to Aeneas," take a look at the other Testa drawing here. The lovely pen sketch of "The Holy Family in Egypt Accompanied by Angels" (c. 1640) shows the artist in an entirely different creative mode. Here he is quickly setting down an idea for a composition. As with the Rubens studies, the figures are rendered with spare, graceful lines, but they are so well realized you'll have no trouble at all appreciating Testa's superb abilities as a draftsman.

"Old Master Drawings from the National Gallery of Scotland" is an enchanting and instructive exhibition, one that reinforces the enduring power of great draftsmanship and, by extension, laments the apparent demise of this most natural and intuitive of the graphic arts. It closes here Sept. 23, then travels to the Kimbell Art Museum in Fort Worth.