SO RICH are the pickings in the field of children's books that my list of the year's 10 best has swollen to a stubborn dozen. One rule of thumb has been to exclude books that are so rarefied or ambitious as to appeal primarily to parents; children will tolerate a book designed to improve their minds but never at the expense of "a good story." That still leaves a very mixed top 12, likely to appeal to various ages and tastes, but all capable of stretching a child's experience, through distinction of language or art or both, without failing to amuse or to provide the emotional satisfaction of an "ending."

In the picture-book category, Leontyne Price's retelling of the story of Verdi's opera, Aida (Gulliver/ Harcourt Brace Jovanovich, $16.95; ages 8-up), opens a child-sized door onto a grown-up art form but also stands out as the year's most sheerly gorgeous, thanks to Leo and Diane Dillon's illustrations. Done in acrylics on marbleized paper, these scenes from the tale of the enslaved Ethiopian princess and her impossible love for an Egyptian war hero seem to glow, page by page, with an eerie inner light -- umber, sea-green and deep blue shading to an unearthly purple, the signature of royalty and death. Price, herself a famous Aida, is an authoritative narrator, but the Dillons' pictures are transcendent, pulling off the near-impossible feat of suggesting in a different medium the thrilling beauty of Verdi's music.

A familiar fairytale gets star treatment in Fred Marcellino's spirited rendering of Perrault's Puss in Boots (Farrar, Straus and Giroux, $14.95; ages 5-up). Playing with the conventions and perspectives of high art, Marcellino brings out hidden dimensions of the story by superimposing his caste of comic animal and human characters -- headed by a superbly boastful, thigh-booted, upright Puss -- onto scenes of sumptuous 17th-century elegance.

From the elaborate glories of old Europe to the simplicity of the New World: "Near the end of March, 1845, I borrowed an axe and went down to the woods by Walden Pond . . ." The record of Henry David Thoreau's solitary two-year sojourn in a forest-bound cabin by a pond was not written for children, but has been made accessible to them through Steve Lowe's careful selection of passages from the original in Walden (Philomel, $14.95; ages 6-10), given fresh life by Robert Sabuda's light-filled linoleum cuts.

Over two centuries' worth of American history pack Alice Provensen's lively The Buck Stops Here: The Presidents of the United States (Harper & Row, $17.95; ages 7-12), an illustrated primer of chief executives from George Washington through Bush. Besides helping kids get their presidents in order, each busy, full-page spread helps link this or that individual to the events of his day. And Provensen's irreverent rhyming couplets skewer them like butterflies: "Fifteen, James Buchanan couldn't/ Keep united states that wouldn't"; "Eisenhower, Thirty-four,/ Inconcluded one more war."

I can't resist including one more picture book just because it takes itself, as Chesterton said of angels, lightly: poet Nancy Willard's The High Rise Glorious Skittle Skat Roarious Sky Pie Angel Food Cake (Harcourt Brace Jovanovich, $15.95; ages 5-10). As insubstantial as the confection it celebrates, it's the offbeat story of a girl who wants to give her mother the birthday cake of her dreams -- and how she does so with a little help from celestial friends. Richard Jesse Watson's egg tempera illustrations are suitably rich and golden and airy, lent added interest by his habit of taking, from time to time, an angel's-eye view of doings below.

Partway between picture book and fiction proper is the much-heralded Crow and Weasel (North Point Press, $16.95; ages 10-up), a novella-length fable and genuinely stirring adventure story by Barry Lopez of Arctic Dreams fame, stunningly illustrated by Tom Pohrt. Drawing on the traditions and imagery of North American Indian cultures, it tells of two young men, still in the form of animals, who set out to travel further north than anyone of their tribe has ever gone. In the course of this tremendous journey, Crow and Weasel learn much, most of it having to do with Lopez's ideas about the relationships between imagination and landscape, people and environment.

Another "in-between-categories" book is a surprisingly sunny and guileless offering from a pair who have collaborated on some much darker stuff: Esio Trot, by Roald Dahl, with illustrations by Quentin Blake (Viking, $14.95; ages 5-10). Spell the title backwards and you'll have the theme of the book, which is a sweet, funny, little tale of how timid old Mr. Hoppy uses his smarts about tortoises to win the heart and hand of beauteous, tortoise-loving Mrs. Silver in the apartment below. (Note for improvement-minded parents: This book features some very subtle mathematical plotting.)

Of 1990's books for older children, several are outstanding. Most unexpected, perhaps, was Gary Paulsen's autobiographical Woodsong (Bradbury Press, $12.95; ages 10-up). Avoiding the rhetorical and sentimental excess that mars some of his fiction, Paulsen describes with sometimes appalling immediacy how he learned to know and run sled-dogs in his native northern Minnesota and his experiences competing in his first Iditarod, the grueling 1,180-mile dogsled race across Alaska. "It is like going back ten, twelve thousand years, running over these mountains with a dog team. Like becoming a true human -- a human before we became cluttered by civilization. Like going inside and becoming a cave painting."

Igniting young imaginations in a different way is an anti-romantic historical novel of 17th-century Boston: Saturnalia, by the prolific and versatile Paul Fleischman (Harper & Row, $12.95; ages 12-up). Set in the aftermath of the Puritans' wars against the Indians, it tells the story of a captive Narragansett boy, now a printer's apprentice, caught between two worlds, two visions of his future. In language at once extravagant and exact, Fleischman draws a quiet parallel between the harsh Boston winter and the even harsher moral strictures of Puritan life.

Fleischman is probably the closest thing American children's literature has to England's William Mayne, who this year adds to his own long list of dense, demanding, poetic novels for young readers the marvelously exciting story of a 6-year-old boy captured by eagles: Antar and the Eagles (Delacorte, $13.95; ages 10-up). Like Barry Lopez's Crow and Weasel, who learn what it means to experience "the intriguing life of another people," Antar finds his horizons unimaginably stretched by his life in the high, cold mountains with these huge and mysterious birds.

An English author of a different stripe is science fiction writer Terry Pratchett, who puts on yet another hat with his disarming satire for children, Truckers (Delacorte, $14.95; ages 10-up). His heroes are the Borrower-sized nomes, who live peacefully under the floorboards of an enormous department store until ominous signs ("Everything Must Go") suggest that their whole world is about to come crashing down. How the nomes, under the leadership of the philosophical and language-addicted Masklin, find their way to a new life Outside makes for hilarious, but thought-provoking reading.

Last but not least is a new book from that familiar magician of nonsense, Daniel Pinkwater. Borgel (Macmillan, $12.95; ages 10-14) takes its title from 111-year-old Uncle Borgel, who moves in uninvited one day with the Spellbound family. Nobody in the family except young Melvin can make head or tail of Uncle Borgel, so Melvin is the one who is invited along on a whirlwind journey through time, which is like a map of New Jersey, and space, which is like a poppyseed bagel (think about it), in Borgel's 1937 Dorbzeldge sedan. Absurdity is the order of the day, but layers of meaning sneakily accrue until the quest for the Great Popsicle, which gradually absorbs the travelers, astonishingly takes on aspects of the sublime. Elizabeth Ward frequently writes about children's books for Book World.