"Master Drawings from Titian to Picasso: The Curtis O. Baer Collection," on view in the West Building of the National Gallery of Art, is a sequence of surprises: Here is Maarten van Heemskerck's patient Job (1559) riding on a tortoise. Here is Rubens' thick-necked Hercules (uncannily resembling a bearded Marlon Brando), and Gismondo Buonarroti, Michelangelo's kid brother, preparing for war, by Baccio del Bianco.

Paintings call the viewer's eye from across the room. But these small sheets are different, quieter, more intimate. Each asks us to peer closely -- and to ignore its neighbors -- and not one of them prepares us for what will appear next.

Only after we have studied all 100 drawings, one after another, do we begin to sense how they fit together, and that they form a collection. Each was bought by Curtis Baer (1898-1976). Together they present a portrait of his taste.

Though a careful connoisseur, he was a bit old fashioned. "For many years," he wrote, he'd been "blind to van Gogh." His European education had been both classical and rigorous -- he took Latin for nine years, and Greek for half a dozen, before entering the University of Freiburg where he studied art history with Friedla nder and philosophy with Heidegger. Baer emigrated to New York in 1940. It was there he earned the money, in the import-export business, with which he bought his art.

"At the sight of a drawing I really want," he wrote, "a bell rings at once." But Baer tried not to heed it. He did his best to "stifle my impulse to buy," patiently waiting until "the first lightning impulse" had settled down "to a more permanent glow."

"The ring of the bell often proves to be false," he wrote.

He often postponed buying, preferring to prolong that state of indecision that he once described as "both harrowing and delicious." When at last he bought, he bought very well indeed. His collection is regarded now as one of the finest still in private hands.

The Baer collection does not stress one artist, one region or one time, but there are certain sorts of drawing to which his eye returned time and time again.

He was particularly attracted to airy, subtle landscapes. More than 30 landscapes are included in his show. The best of them -- a view of Renaissance Fiesole by Fra Bartolommeo, a row of trees by Fragonard and a rare "View of Mt. Vesuvius" by Degas -- share a stunning softness. They feel as if they were not so much drawn, as breathed.

Baer also liked the play of sunlight on gently rounded forms -- a muscled knee drawn by Giovanni Battista Tiepolo in the 18th century, a Roman tower depicted by Jacob van der Ulft in 1661 or a billowing white cloud drawn by the otherwise anonymous "Master of the Blue Paper Drawings" in 18th-century France. Not all the roundnesses in Baer's drawings are made round by shading. Sometimes outline is enough. Consider, for example, two of his best sheets, a rare study of three hands by Constantin Brancusi and a "Head of a Young Woman" (1919) by Henri Matisse.

Baer was also taken by the unhesitant assurance of free, untrammeled line. The swirls that form the king's sleeve in a 1637 drawing by Guercino, the boldly crosshatched muscles of an arm by Passarotti and the unafraid scribbling of Kokoschka brought Baer's eye delight.

Not all of his concerns were esthetic. Oddities intrigued him. That the posing engineer is Michelangelo's youngest brother no doubt pleased him greatly. So did the strangeness of Job's tortoise's shell, the seated skeleton grinning by the bed in that late Daumier and a pair of moody landscapes by the writer Victor Hugo -- an unexpected presence in so refined a collection.

Baer often liked to think that a "guest," a "spiritual presence" -- like the genie in Aladdin's lamp -- inhabited his drawings.

"Here," he wrote, "lies the unique nature of what is called, superficially enough, the 'visual arts.' While also in a piece of music, or in a poem, we comprehend a spiritual entity, it has no corporeal form." But the drawing "exists both materially and immaterially -- the little square of paper contains a sort of magic."

The exhibition was organized by Eric M. Zafran, formerly of the High Museum, Atlanta, now of the Walters Art Gallery, Baltimore. Andrew Robison, curator of the National Gallery's department of graphic arts, helped pick its 100 drawings. The Baer exhibition will travel to Indianapolis, Sarasota, Fla., Atlanta, Baltimore and UCLA after closing here Oct. 6.