IN A TIME when art -- and life -- can seem so hard, 112 pieces of unusually viewer-friendly art comes hilariously, affectionately and hallucinatorily to our rescue in an irresistible collection of eye candy called "Deceptions and Illusions: Five Centuries of Trompe l'Oeil Painting" at the National Gallery's East Building.

Trompe l'oeil, the "tricks the eye" super-realism that allows characters to lean out of their portrait frames and lures onlookers to try to pick painted grapes, is at once an artistic challenge, a meditation on mortality and the meaning of life, and the greatest good-humored joke that visual artists can play ontheir audience. Arranged over two floors (mind the stairs!) and by stylistic puns that span the centuries, "Deceptions" includes pieces from all over Europe as well as the United States and must have been a sort of busman's holiday for curator Sybille Ebert-Schifferer of Rome's Max Planck Institute for Art History. It's only a shame the show won't be traveling to enlighten -- and to lighten -- the downhearted of other cities.

A few pieces seem less than tricky -- sometimes a still life is just a cigar -- but among the truly impressive are Charles Willson Peale's 1795 double portrait of his sons Raphaelle and Titian climbing a staircase in Peale's museum (a sleight of hand so well executed that George Washington is reported to have bowed to them); Wendell Castle's "Ghost Clock," which portrays a grandfather clock swathed in a stupefyingly convincing dust cover (down to the string and hem stitching); Jefferson David Chalfant's painting of a two-cent Lincoln stamp next to the real thing, appropriately called "Which Is Which?" (the owner forgot); and the flabbergasting bas-relief sculpture niche called "Allegory of the Treaty of Aix-la-Chappelle" by Jacob de Wit, which looks as if it fell right off a memorial lobby complete with limestone-gray putti, cornucopia and tiny classical frieze.

Domenico Remps's 17th-century "Cabinet of Curiosities," presented to Ferdinando de' Medici, employs layer upon layer of frames, including a sill, outer "glass" doors (with cracked panes) and an inner case filled with collectibles such as a scarab, miniatures, sketches, shells, a skull and a clever concave mirror reflecting the room the viewer is supposedly standing in. Louis-Leopold Boilly's "Collection of Drawings" has such realistic glass shards that visitors often forget not to lean on the equally astonishing tabletop beneath as they peer around its sides.

A 17th-century Flemish artist named Franciscus Gijsbrechts painted not one but both sides of a "window" stuffed with the usual mail and personal effects. Samuel van Hoogstraten's 1662 "View Down a Corridor," a miniature fun house of perspective and corridors, resembles nothing so much as one of those interactive video games in which you can move about a room; unfortunately, the peephole door has been removed, so while you can admire it, and look at a wall-size photo of the effect, it's not as much fun as it might be. (Perhaps a virtual version?)

Several of the other pieces would also be blockbusters if they had not been played false by time -- if we still stuccoed the interiors against which mottled white backgrounds would be invisible (and Boilly's "ivory crucifix" might have hung). The wood-paneled hall reflected in Remps's mirror would probably have been a fair bet in 17th-century Florence. John Haberle's 1887 assortment of old coins and stamps and a fantastically creased and worn dollar bill got him in trouble at the time, as it was deemed forgery; but the in-joke was that all the other items were obsolete -- worthless copies of worthless possessions. (Memento moni?)

The bulletin board has replaced the letter racks of the 19th century, with their lattice of pinned ribbons that held letters and small toiletries, so while the perfection of these envelopes and stamps and hair combs is clear to us, the catchall itself doesn't have the three-D presumption it would to its original audience. Even so, the pulled and frayed silk of American trompe l'oeil superstar William Michael Harnett is nearly irresistible. Harnett has a half-dozen fascinating pieces in the exhibit, most using such racks or wooden panels as background; the widely reproduced "After the Hunt" is especially fine, its apparent depth accentuated by subtle layers of "sunlight" that glow softly on the rabbit's plush coat and the worn door and glints brilliantly on the ivory knife handle, hound master's horn and the palpably iron trigger.

While the exhibition title refers to the last 500 years, such painterly legerdemain goes back to the mosaics of Roman and Pompeiian villas. And whether in tribute (or critical twist) or by serendipitous inspiration, certain items or backdrops have been employed by trompe l'oeil artists for millennia.

Among the most common and long-running tricks of the trade is the fly that seems to have just landed on the painting (or the subject) or become squashed in the pages of an otherwise conventionally illuminated prayer book. A 15th-century painting of Saint Catherine of Alexandria seems almost brazenly jokey; it shows the saint purely in the style of the times, a little soft-focus, a mix of submission and sensuality but with a sharply realistic fly on the wall, whose "real"-life size further destroys the illusion of the saint's perhaps foot-tall body. Skulls made good details not only because they were so very round but because as memento mori, reminders of the transitoriness of life, they were also puns on the permanence of art. Similarly, an 1890s American painting of a parrot, whose "label" describes it as stuffed, is a triple pun on false life.

The false curtain in many paintings refers to the one that, according to Pliny, the Greek artist Parrhasios painted in a trompe l'oeil duel that he won when his rival tried to sweep it aside. Raphaelle Peale, who appears in his father's stairway panel, made fun of his contemporaries' prudery by drawing a drapery, as it were, across a version of Venus rising from the sea.

Even those early Pompeiian mosaics included hunting trophies hanging from nails that cast dimensionally confusing shadows. One of the show's most obvious masterpieces is the 17th-century door panel by Dutch artist Jan van der Vaart that portrays a violin hanging from a (real) peg, its creamy caramel highlights seemingly from a wood far finer than the "surface" beneath it.

One might argue that some of the more modern slants on these old tricks, such as the pieces by Roy Lichtenstein and Jasper Johns, are solely referential; and that the point of Warhol's boxes of Brillo was not so much that observers thought they were real but that he could convince them that they were art. Pistoletto's 1962 "Mirror With an Easel" turns the entire gallery into a studio, reversing the role of observer and artist, which is at least clever. However, Rene Magritte's "La Condition Humaine" from 1933 is a great punch line: a painting of a landscape, set on an easel so that it fits perfectly over the view from the open (and, yes, curtained) window that is also, of course, painted. Just ask the girl staring at it.

There are some pieces too surprising to spoil by describing. The gallery staffers obviously became infected with the fun, as they have planted a few jokes of their own, small and large, throughout the exhibit. And it is not giving those away to point out that the museum has also, well, planted a prime bit of ultra-modern trompe l'oeil alongside Peale's staircase effect: a group of artistically faded but artificial ferns and fig trees.

DECEPTIONS AND ILLUSIONS: FIVE CENTURIES OF TROMPE L'OEIL PAINTING -- Through March 2 at the National Gallery of Art, East Building, Fourth Street and Constitution Avenue NW (Metro: Judiciary Square). 202-737-4215. Open Mondays through Saturdays 10 to 5, Sundays 11 to 6. Free.

Wendell Castle's "Ghost Clock," above, and Rene Magritte's "La Condition Humaine," at left.