John Frederick Peto's still lifes are modest, stately, strange. He mined an old tradition, and died in 1907, and yet his pictures even now elude full comprehension. Apparently straightforward, they are deeply enigmatic. They have the look of objects made to trick the eye. But they do not do so really. They work upon the mind.

At first glimpse they seem solid. It is only on second glance they start to slip away.

"Important Information Inside: The Still Life Paintings of John F. Peto," his first museum solo show, goes on view today at the National Gallery of Art. John Wilmerding's exhibit rightly takes its title from a legend that appears, without explanation, on an empty orange envelope in one of Peto's still lifes. His spare, imposing paintings have mysteries within them, and missing clues and veiled truths. Perhaps it is no wonder they have been so long misread.

Their worn and humble objects--their wooden matches, pipes and mugs, their tattered books and candlesticks--seem statements of dull fact. Yet they feel like meditations on transience and decay. Peto was a recluse. Most of his best pictures--his table tops, his letter racks, his shelves of books, his battered doors--were painted in The Studio, his Island Heights, N.J., house, while his senile aunt upstairs rattled her locked door. Today it is apparent that his haunting pictures are idiosyncratic and, at least to some degree, autobiographical. Yet not so long ago they were frequently mistaken for the sharply focused still lifes of his cooler, less mysterious colleague, William Michael Harnett (1848-1892).

Perhaps the strangest quality of Peto's glowing still lifes is the way they've somehow managed to rotate in art's history. Once they pointed backward. Peto was no rebel, no dashing avant-gardist, and his paintings, when still new, seemed entirely dependent on examples from the past. Their precedents were clear. They were obviously indebted to Dutch 17th-century still lifes, and to Harnett's compositions, and to the "Philadelphia table-top tradition" established in that city by such men as Raphaelle Peale (1744-1825).

But the Petos at the National Gallery have another aura. They once looked retrogressive. Today they feel prophetic. "It is one of the rich fascinations of Peto's art," writes Wilmerding, the museum's senior curator, "that it gives such a broad range of hints of coming esthetic concerns in modern art."

In the speculative book that accompanies his show, Wilmerding connects the objects Peto chose to paint--playing cards and pipes, newspapers and violins--with those picked by the cubists. In Peto's private reveries Wilmerding detects echoes of those prompted by Joseph Cornell's boxes. Peto painted dollar bills as Andy Warhol would do later, and the little Lincoln portraits stuck into his letter racks and tacked to his wood doors suggest the way that Robert Rauschenberg would later use the likeness of the murdered John F. Kennedy. Peto seems more modern now than he did when alive.

His subjects are the subjects found in other trompe-l'oeil pictures, but Peto's aim is different. He does not fool the eye, as Harnett does so often. Peto's detailing is broad. One cannot read the texts of the newspapers he paints. His extraordinary colors--his oranges and yellows, lavenders and greens--are not those seen in real life. His torn, untitled books look far less like real volumes than they do like nearly abstract passages of paint.

Harnett's polished still lifes, and those produced in Holland, and Raphaelle Peale's as well, delight us with their details--the fuzz on that fresh peach, the glint of that clean glass. Harnett painted dollar bills so accurately that once, in 1866, he was arrested as a forger. But Peto never asks us to forget his brush. His finest little still lifes here--"Brass Kettle," for example, or "Candlestick, Pipe and Mug," or "Cake, Lemon, Strawberries and Glass"--seem as moody as Morandi's, as surreal as Magritte's.

There is alchemy at work here. Peto understood the temporality of things. Unlike other painters, the photo-realists, for instance, he rarely tried to paint the undamaged or the clean. His envelopes are torn, his books are never new. He would not even let his wife polish the brass pots and pans around the house. He preferred to see them tarnished.

His matches may be burnt, his nails may be rusted, his wood doors cracked and weathered, but his early pictures are almost never gloomy. They often hint at mild pleasures, at music and at sweet desserts, at evenings spent in candlelight with a clay pipe and a book. His family has preserved his house in Island Heights and it still contains a number of the props he chose to paint. Peto, who was born in 1854 and who studied (as had Harnett and Thomas Eakins) at the Pennsylvania Academy of the Fine Arts, did not linger long in busy Philadelphia. He preferred seclusion. He must have spent long hours in undirected musing. One sees that in his paintings. They slide one into reverie. They are portraits less of objects than of moods.

Such reveries are fragile, and Peto's pictures, too, are often delicately balanced. The old candlestick one sees in his "The Writers Table" is leaning most precariously, the pewter mug appears about to tumble, and the cover of that old book is hanging by a thread. To look upon that table is to know the man who worked there.

All of Peto's pictures are to some degree self-portraits--"indexes," writes Wilmerding, "of his autobiography." We now know that the artist spent his last years in great pain. He died of Bright's disease. Pain fills his late pictures. When his father died, he painted works suffused with loss, some of which include a rusted bowie knife picked up on the Gettysburg battlefield, and likenesses of Lincoln, another father lost. "The Cup We All Race 4" shows a battered tin cup hanging on a cracked wood plank carved with those strange words. Is the cup there to suggest death's inevitability, the pleadings of a beggar, or the grail of the common man? Peto does not answer. Here, as always, he returns the viewer's wandering, wondering mind to the work of art.

The Peales had greater influence, Harnett had greater gifts. Peto may not rank as a major master, but he made wondrous pictures. Wilmerding, who organized the gallery's grand Luminist exhibit, has once again arranged a most impressive show. It will travel to the Amon Carter Museum, in Fort Worth, after closing here May 30.