The theme is familiar: Spoiled, rather unpleasant...

The theme is familiar: Spoiled, rather unpleasant children are rescued/captured by animals. Frightened at first, the children become friends with the animals, adapting to their new surroundings. In the course of a quest, the children encounter challenges of strength and courage; self-sufficiency replaces self-centeredness, and the children, no longer whining brats but agreeable individuals, return to their families. In short, the kids grow up.

Here are two imaginative, elegantly written books on this theme for young readers (ages 9 to 12 and up). R-T, Margaret and the Rats of NIMH by Jane Leslie Conly (Harper: $12.95; 288 pp., illustrated by Leonard Lubin) is the second sequel to the 1971 Newbery Medal winner, “Mrs. Fribby and the Rats of NIMH,” by Robert C. O’Brien, Conly’s father. In the original book, super-intelligent rats escaped from the laboratories at NIMH and founded a colony in Thorn Valley.

Conly’s first sequel, “Racso and the Rats of NIMH,” also won several awards. In her new book, the rats continue to thrive, but always fear discovery by humans who might return them to the director of the experiment.

Enter Margaret, a doltish 10-year-old who sneaks sweets and wholeheartedly resents her little brother Artie, a sickly kid who doesn’t speak. When Margaret and Artie get lost in the woods, the rats find them. Margaret and her brother, whose name is misunderstood by the rats as “R-T,” go to live with the rats. The children’s transformation begins.

The rats send Margaret on a quest, to move the nest of a predatory hawk on a high cliff. Her success proves to the rats--but also to Margaret--that she is strong and capable. Meanwhile, R-T’s friendship with a young rat named Christopher improves his asthmatic condition; he begins to speak.

It’s a logical place to end, but Conly takes the story into what happens when Margaret and Artie go home. Now Margaret faces a different kind of challenge, and the author explores the loneliness of keeping a secret, especially one as big as super-intelligent rats who talk.

When two of their rat friends come to the city to visit, Margaret sneaks them into an amusement park closed for the night. (At this point the magic faded a bit for me; I could imagine the rats in a sylvan setting but not on a Tilt-a-Whirl at midnight). They are spotted; the secret begins to leak out, and soon a whole bunch of people are on their way to Thorn Valley. But Margaret--and Artie--save the day, and the story ends with an arrow pointing to still another sequel.

Antar and the Eagles by English author William Mayne (Delacorte: $13.95; 166 pp.) uses the same thematic material but with different effect. While Margaret and R-T are clearly contemporary Americans, city kids who ride subways and watch VCRs, Antar’s story, set in the sometime-past and the somewhere-else, is less familiar, more fantastic.

Antar, just old enough to start school, is seized by the Great Eagle and taken from his village for a long and painful journey. At last, he is delivered to an eagle’s nest, complete with fledglings who look on this tender young morsel as their next meal. Eventually, Antar gets used to his nest-mates and manages to choke down a gob of raw meat brought by Garak, the sentinel eagle who is to be his mentor.

While the rats of NIMH are human-like, weaving baskets, planting gardens, preparing their delicious vegetarian food for Margaret and Artie, the eagles provide no such luxuries. Nor do the eagles become like humans; Antar must become like an eagle, learning to recognize them by their markings, to understand their language, to communicate with them. There is something more he must learn: Antar, now called Gadar by the eagles, painstakingly stitches molted feathers to his clothes. And flies.

As he becomes stronger, braver and cleverer, Antar also is given his quest: He must find the egg, stolen from a king in a distant kingdom, from which the next Great Eagle is to hatch. Once the boy manages to retrieve the egg, there is the arduous journey back and the impossible task of delivering the egg intact. Dangers lurk on every page before Antar manages to return to his own fireside, parting as reluctantly from the eagles as Margaret and Artie did from the rats.

Both books are satisfying in a number of ways. The societies of the animals carry the message that the individual rat/eagle--and by extension, human--is less important than the community; that kids can do more than they think they can; that home is not such a bad place after all.

These make an excellent pair to read back to back. Although the messages are the same, the styles are strikingly different, each bringing a special reward for the reader.