Picture-book illustration isn't a pure art form; it's an applied one. As the illustrator Robert Ingpen has said, it's "pictures telling stories." The pictures aren't there for their own sake but to serve words or ideas. At least, the best picture books do that. The worst have art exploding all over the page, sidelining or hijacking words and turning the flow of ideas into an obstacle course. Four new books achieve the essential balance without being showy about it.

Zip. Zilch. Nada.

Patrick McDonnell, creator of the popular comic strip "Mutts," pulls it off in The Gift of Nothing (Little, Brown, $14.99; ages 4-up), a mellow paean to anti-materialism that should ideally be handed out now, before holiday gift mania really kicks in. Spare drawings done in black, white and a seasonal touch of red reinforce the Zen-inspired idea that less is more. The two main characters are the strip's stars, Mooch the cat and Earl the dog, sprung from their strip cages. "It was a special day and Mooch wanted to give his best friend, Earl, a gift. But what to get him?" Earl already has everything: a bowl, a bed, a chew toy, each shown in all its humble glory on its own page. So Mooch comes up with a plan. He will give Earl the gift of nothing.

Thus begins a quick-fire riff that turns the word -- and the idea -- inside out. Nothing, it seems, is hard to come by. Mooch is baffled. Aren't people always saying there's "nothing on TV" and they have "nothing to do"? Doesn't look that way to him. Finally he hears his owner, Millie, complain after a trip to the store, "There was nothing to buy!" Relieved, Mooch races down there, only to find "many, many, many somethings. The latest this, the newest that. . . . " He plods home through the snow, the picture of disappointment. It won't be revealed here how Mooch eventually locates "plenty of nothing," but the gift proves all Earl could wish for. The expressions of both are, appropriately, priceless. The Gift of Nothing is really something.

Eyeballin'

A Good Night Walk, by Elisha Cooper (Orchard/Scholastic, $16.99; ages 3-6) is another picture book that is so simple in idea and execution that it could easily slip under the radar. It shouldn't. "Let's go for a walk," says a mom, peeking out the front door of a suburban house marked No. 2, "and see what we can see, before it's time for bed." See what we can see: Those five quiet words supply both plot and method as the invisible protagonists (the mom, presumably, but one child? two?) take a leisurely evening stroll along their street, all the way to No. 14 and back again. What they see is stripped across the top four-fifths of each two-page spread. A commentary runs across the bottom, pointing things out: "The neighbor next door has finished her gardening. She rests against the red wheelbarrow under the oak tree. The leaves of the oak tree bend in the wind." (The echo of William Carlos Williams's poem about the extraordinariness of ordinary things is surely intentional: "so much depends upon/ a red wheel barrow/ glazed with rain water/ beside the white chickens.")

Other players -- squirrels, birds, cat, neighbors doing this and that -- star in their own subplots, lending suspense to the walk back. And over everything, slowly, slowly, the watercolor-blue sky deepens to inky black. As Mom closes the door on moon and night, three beautifully paced sentences sum up the themes of comfort and anticipation: "We're home. It's time for bed. And all we have seen, we will see again, when we walk along the block in the morning."

Ursa Major

Elemental in a different way is Nicola Davies's Ice Bear: In the Steps of the Polar Bear, dazzlingly illustrated by Gary Blythe (Candlewick, $16.99; ages 4-8). An Inuit narrator describes the polar bear's habits and shrinking habitat. There's no cuteness, no anthropomorphizing, just unfailingly interesting information delivered with lyrical matter-of-factness: "No frost can steal POLAR BEAR's heat. It has a double coat, one of fat, four fingers deep, and one of fur. . . . and underneath, the skin is black to soak up heat." The paintings also blend science and poetry. Most take up entire borderless double pages, as if anything less would not do for either Arctic panoramas or the bears' massive bulk, and they are seriously beautiful. But they are precisely observed, too. One spread shows nothing but a life-size snowy paw print ("A single paw would fill this page -- and shred the paper with its claws"). A close-up of a mother -- so big we see only her head -- nestling her sleeping cub is as lifelike as a still from the panda cam at the National Zoo. In a flower-strewn summer meadow, a hungry bear rips out grass. Natural history for beginners -- at its best.

Wild and Woolly

Finally, there's Brave Charlotte (Bloomsbury, $16.95; ages 4-8), a classically simple tale by the Finnish-born German writer Anu Stohner that is raised a notch by Henrike Wilson's illustrations. Charlotte is a sheep, but not one of your shy, dithering, conformist sheep. She climbs trees and mountains, swims in the fast-running stream and stands by the dangerously busy road so she can watch the traffic. The other sheep are freaked out. A crisis is inevitable. But it's the shepherd who falls and breaks his leg, and it's maverick Charlotte -- fresh from her self-devised Outward Bound program -- who travels miles for help. The story is funny and satisfying, but it's the pictures that stay with you: the silly sheep with their staring yellow eyes, Charlotte with her black beady ones, Charlotte snoozing on a bough or perched smugly on a cloud-wreathed pinnacle, Charlotte hitching a ride on the highway.

And as with all great picture books, the illustrations also hint at unspoken dimensions. Early on, sunny blues, yellows and pinks abound. At anxious moments, the sky turns gray and the clouds thicken. When the crisis hits, it's night, and fog swirls in the valley. The rescue trek takes Charlotte across brooding peaks and down midnight roads. Even as the text reassures -- "It was so nice to roar through the night in the truck that Charlotte was almost sorry to have to get out" -- the picture is shivery-scary. It's that tension, as much as the whimsy, that will keep kids coming back to this book. *

Elizabeth Ward writes Book World's biweekly "For Young Readers" column.