"I knew a little boy," remarked the eminent Soviet children's writer and educator Kornei Chukovsky, "who would often question his mother about where the night went in the morning. Once, coming across a deep ditch whose bottom was dark, he whispered: 'Now I know where the night hides itself.' "

Nearly all children probably wonder about this boy's question. If it is answered for the moment by the discovery of a certain shadowy hole in the ground, it is prompted again by the growing "realism" of the older child, to be satisfied this time by knowledge of the earth's rotation and orbit around the sun. When other, less tractable forms of the question, which is concerned in its fullest emotional reaches with the meaning of loss, continue to resurface, the child -- and then the grown person -- responds yet again, more adroitly perhaps but not less speculatively, whether by writing elegies, contemplating the afterlife or by taking out some insurance.

The poet Mark Strand is an elegist for whom questions of loss -- the loss of a parent, the poignant separation one can feel from one's own past, the loss of self experienced as the imagination presses toward visionary limits -- have had the peculiar urgency and fascination of a radical obsession. In The Planet of Lost Things (to be published next month), his first children's picture book, Strand has attempted to restate this obsession on an imaginative ground accessible to children curious about night, day, lost socks, forgetfulness and other similar mysteries. William PMene du Bois, whose long shelf of festive achievements includes such picture book classics as Otto at Sea, various books about bears, and Lion (reissued this fall by Viking)--he has also been art director of The Paris Review -- is the illustrator.

Strand's book is ambitious in the very fact of its taking on such a many-layered riddle, but confused and divided about the terms of the story's resolution. A boy dreams he has piloted his rocket to a planet he has never in his far-flung imaginary travels observed before, a Borgesian puzzle-planet on which he finds gathered all the dogs that ever strayed from home, all the letters lost in the mail, all the money fallen from people's pockets, all the hats blown away in the wind: a vast collection of collections not less thorough about such intangible losses as forgotten thoughts and unrecorded sounds as about misplaced keys and umbrellas. Going for a walk around the planet, the boy meets two of its inhabitants, a kindly if bewildered man and woman who introduce themselves as an Unknown Soldier and Missing Person. They point out various sights of their world as the three companions wander aimlessly together; the boy himself meanwhile has forgotten where he left his rocket. "That's par for the course up here," says the Unknown Soldier. "No one is supposed to remember." (But how, then, an inquisitive child might logically ask, do he and his friend even recall they are "missing" and "unknown"? remember how to talk?) "Have a balloon," offers the Missing Person, motioning to the accumulated mass of the world's mislaid helium-filled toys.

The trio passes the region inhabited by extinct animals but do not stop there. "Too bad we can't pay them a visit," says the Unknown Soldier, sounding disconcertingly like a tour guide impatient about schedules. (Here the reader wonders whether the powerful images Strand evokes do not actually call for a much longer, more discursive narrative.) "They are dangerous," the Soldier says concerning the animals, "and, besides, it's out of our way." Anticipating the boy's (and reader's) disappointment at this news, the Missing Person promises a still more interesting adventure to come.

"This," she announces at last, "is where everything goes that magicians make disappear."

As rendered by William PMene du Bois with his customary panache and miniaturist's delight in carnival regalia, the boy and his companions do indeed arrive at a colorful stage-flat house of cards, charmingly decked out with magician's tables and turtle doves, top hats, scarves and rabbits. But no performance is in progress, no adventure at hand; moments later, the three wanderers have already departed and the boy has boarded his spacecraft for the flight home, there to awaken in his familiar bed, his dream all but forgotten.

Strad is a master of a certain type of absurdist wit that arises out of his pressing a world of commonplace wishes, fears, thoughts and occurences to their extreme logical limits. The Planet of Lost Things' beguiling, rarefied atmosphere is the aura of the uncanny. In such an atmosphere, so aptly fitted to the open-ended, unself-conscious questioning of children, the final resort to stage magicians' vanished properties is a diminishment, a sentimental reduction of the story's sense of the magical; the boy's "perfect" takeoff as he heads home seems emblematic of a sleek technical exercise at the end of which The Planet of Lost Things remains largely unexplored.

In his first children's picture book, the poet Galway Kinnell has concerned himself with a considerably more modest mystery. How the Alligator Missed Breakfast, with cheerfully diverting watercolor-and-line illustrations by Lynn Munsinger, is an unpretentious, skillfully crafted little story about a rabbit, a crow, a porcupine and an alligator who befriend each other and sort their way through comic episodes involving, among other things, a talking bathtub, an abandoned car, an inexperienced barber and a hapless pair of frying eggs.

In occasional passages in this book's middle pages, the author seems to indulge in a bored parody of children's storybook writing, but Kinnell keeps his humor most of the time, gently teasing the knowing child reader with such mischievous notions as that of a tub which while roaming the countryside stopped dirty children it found along the way. " 'Would you like a bath?' it asked. 'No, thank you,' each child answered politely.'"

19 No, thank you, indeed. The playfulness and benign cunning of moments like this one are endearing to 4- and 5-year-olds more inclined perhaps to be curious about their world than clean behind their ears. And in the one sustained piece of inspired writing in this book, "The Story of Two Eggs," Kinnell has fashioned as shrewd a bit of comic business as will be found in any recent children's book; a story as much in the tradition of nonsense folktales like "The Pancake" as of the vaudeville routines of Laurel and Hardy.

Two eggs were frying together in a pan when "one of the eggs, Boily McPoach by name, said to the other, Egbert Egglesworth, 'Egbert, don't you find it hot in this frying pan?' 'Yes, I do.' replied Egbert. 'Very hot.' 'And doesn't it seem to you it's getting hotter?' said Boily. 'It does,' said Egbert. 'Much hotter.' 'Egbert, I think we are being fried . . .' "

Out of the frying pan they go and into . . . the fire, more or less. Readers of Kinnell's poetry will recognize in this story his wonderful gift as a teller of tall tales as well as certainly the daftest incarnation of his mythic embrace of the image of fire as an emblem of poetic necessity, of living by one's wits. Poor Egbert and Boily! And surely their saga lies worlds apart poetically from, say, the impassioned self-questioning of Kinnell's "Another Night in the Ruins," in which the poet discovers that "as he goes up in flames, his own work/ is/ to open himself/ to be/ the flames . . ."

In How the Alligator Missed Breakfast it is, in any case, the egg story alone that seems written out of necessity; a fair taste, let us say, of children's book writing at its best.