TWENTY YEARS AGO, in a lab full of grade-oriented students peering diligently through microscopes at cytoplasm streaming through elodea cells, our botany professor interrupted his technical explanations to announce, "Look well. What you are looking at right now is as close as any man has come to seeing God." These new books by two justly acclaimed children's authors provide a similar glimpse of the awesome, ungovernable mechanisms of life, and love that spans the arbitrary boundaries we have drawn between genus and species.

The previous fantasies in Jane Langton's series about the Hall family (The Diamond in the Window, The Swing in the Summer House, The Astonishing Stereoscope) were delightful, episodic adventures conjured by a magician's art. In The Fledgling, a departure from that Arabian Nights tradition, wizardry bows to the infinitely more profound and elusive magic of life itself. The story, unlike its predecessors, requires no effort to suspend disbelief; like Charlotte's Web, it merely stretches the laws of nature a bit at the corners rather than defying them altogether.

Little Georgie, eight years old now and "in some kind of funny trouble," develops a passionate longing to fly. Through the love and trust of an elderly wild goose her yearning is fulfilled, to the terror of her family and the malicious, ultimately murderous, delight of their hypocritical neighbors. In the company of her "Goose Prince," Georgie travels gloriously over Concord, Massachusetts, and inherits a shining world beyond it; the goose's final act, the giving of the present he has so lovingly preserved, provides a lovely touch of unexpected grandeur to the ending. The Fledgling is an exciting, articulate story as well as a delicate parable about love, family trust and respect for the intuitive bond between children and wild things.

Madeleine L'Engle's books are peopled by several generations of characters linked by birth, marriage, occupation and friendship, like atoms in a complex carbon molecule. In A Ring of Endless Light, the Austins (Meet the Austins, The Moon by Night, The Young Unicorns) and the Murry-O'Keefe lineage (A Wrinkle in Time, A Wind in the Door, A Swiftly Tilting Planet, etc.) are bridged by young Adam Eddington, home from his adventurous summer job with Dr. O'Keefe (The Arm of the Starfish) to study dolphin communication at the marine biology lab that employs John Austin, Vicky's older brother. Vicky, caught in a bewildering tangle of emotional, sexual and intellectual uncertainties in her 16th year, confronts head-on the eternal nightmare of death. When even the extraordinary warmth, humor and sturdy common sense of family and friends prove inadequate to her shock and bitterness, her uncanny ability to communicate with the dolphins, and their final exuberant lesson, rescue her from the ultimate selfishness of despair. The cosmic battle between light and darkness, good and evil, love and indifference, personified in the mythic fantasies of the Wrinkle in Time series, here is waged compellingly in its rightful place: within ourselves. "You know what we need is a new God," L'Engle wrote in Camilla (1951), "We need a God who's big enough for the atomic age." What was needed was not a new god, but a higher resolution instrument, one adjusted with increasing clarity of focus by a gifted writer in the intervening years.

By a curious sort of parallel evolution, Jane Langton and Madeleine L'Engle have traveled widely divergent routes to a singular affirmation of life. Faced with devastating loss, both Georgie and Vicky are supported in their grief by trusting, literate, cohesive families, and both find comfort in the wisdom of creatures untainted by the empty values of progress and civilization. "In youth, before I lost my senses, I can remember that I was all alive . . . . In Wildness is the preservation of the World," writes Thoreau in the epigraph to The Fledgling. The children in these two books are "all alive," still receptive to the great design of the universe, and their rapport with things wild and ungovernable preserves them from thoughtless mediocrity. In a culture obsessed with consumption, instant gratification and disposable lives, loves, families and friends, such children and the intelligent families that produce them are threatened with extinction. Such books as these will preserve the model for a dwindling audience of thoughtful, sensitve young readers.