AN HOUR before curtain time at the American Place Theater in New York, the children in the cast of Really Rosie are playing a vigorous game of freeze tag around the fountain in the adjecent plaza. Four of us approach but they see only one, and they begin shouting at once. "Maurice! Maurice! Maurice is here! Are you coming to the show tonight, Maurice? Oh, please come to the show tonight."

They are gleeful: Maurice is coming to the show tonight. Immediately the 52-year-old man they call Maurice is surrounded by eight or 10 laughing, clamoring youngsters, tugging at his hands, his coat, each vying for the attention of their friend Maurice Sendak, who also designed the production and wrote the book and lyrics (Carole King wrote the music) of the show they are appearing in. The musical is itself an expanded version of his 1975 animated television special, which originated in his book The Sign on Rosie's Door (1960) and in the four miniature volumes of the hugely successful Nutshell Library (1962): Alligators All Around, Chicken Soup with Rice, One Was Johnny, and Pierre, the boy who says only "I don't care" even when a lion fancies him for dinner.

Countless children and their parents committed these books to memory -- learned by heart, as it were -- through repeated, demanded readings. One of them is my daughter, now 17, who still remembers and who is among us this evening in mid-March as we head toward a nearby reataruant for a drink before the 7 o'clock curtain. (The curtain is early to make it easier for children to attend.) It is to her, the youngest of the group that Sendak directs his attention. He wants to know, among other things, what books she likes best. When she says Higglety Pigglety Pop! or There Must Be More to Life (1967), he says that is his favorite, too, and that the dog Jennie, its insouciant heroine, was modelled after his own beloved Sealyham terrier who has gone on, as he puts it in the book, "to Castle Yonder." My daughter tells him that she used to read it in a special tree, and one afternoon left it in a private place there, intending to return to it in the morning. It rained during the night and the book got soaked. But it dried out, and it now resides well-thumbed, rainmarked but intact on her shelf. "You read it in a tree," Sendak murmurs. "That means you really liked it." Unlike Pierre of his cautionary tale, Maurice Sendak does care. He cares very much, in fact. He cares about the people he meets, the books he writes and illustrates, the unseen and unknown readers who treasure them, the drawings and paintings he makes, the Mozart he loves, the operas he desings (including a version of his classic Caldecott Medal book Where the Wild Things Are that the Brussels Opera staged last November), the dogs he adores and fusses over, the friends who love him, and the show he is seeing for yet another time tonight, catching a lighting flaw here, crediting a good new piece of business there.

In the show Rosie is an artist, surviving and beginning to flourish in the Brooklyn of Sendak's own childhood. A born actress, a budding Barbara Streisand, as she has been described, the power of her vivid imagination (in which she, of course, stars) enthralls the Nutshell kids of her neighborhood and releases them to their own fantisies which Rosie dominates but does not entirely control, other people and the rougher realities of the world being less malleable to out wishes than are our dreams: the correspondence of life to art is proximate at best. Rosie's dream -- the childlike dream that may become more sophisticated with the age of the artist -- is to hew the world to her idea of the artist make life what it ought to be but only momentarily is. She sings; In dreams, it seems, I always see Avenue P as it ought to be -- a terrific place for people like me.

"But the line from the show that always moves me," Sendak says later over dinner, "the line that brings tears to my eyes every time I hear it, is 'on an ordinary day like today.' When you realize that all days are ordinary and then things happen, arbitrarily, precipitously . . . .that the most amazing things happen on just any ordinary day, the most calamitous things. When I had my coronary in 1967 I remember thinking, 'It's only Tuesday . . . that this event that was terrifying to me could occur on just an ordinary day like Tuesday . . . When Kathy sings that line in the show it makes her conscious of time, of time as something more than just what's happening minute by minute." It makes her conscious of this minute." What that line makes Kathy realize is the power of art, which (like catastrophe) can appear to make time stand still. Thus the raw experience of our ordinary days is heightened, illumined and transmuted, and our unique experience joined to the common flow.

When Really Rosie first appeared on television, Sendak wrote, "I loved Rosie. She knew how to get through a day . . . Rosie [is] the living thread, the connecting link, between me in my window and the outside over there. I did, finally, get outside over there. In 1956, after illustrating some 20 books by various writers, I did a Rosie and wrote my own." His own, the first he both wrote and illustrated, was Kenny's Window. The eleventh and most recent, competing the trilogy begun with Wild Things and continued with In the Night Kitchen (1970), is Outside Over There which started with a few lines that came unbidden in 1974. "Even then," he says when reminded of these words he wrote about Rosie in 1975, words that bemuse him now, "even then the title was heavy in my head." i OUTSIDE OVER THERE

IN THE FIRST book, Maurice Sendak poses seven riddles. The sixth is "What looks inside and what looks outside?" The answer is Kenny's window. Sendak has many windows, shaded and clear, looking in on himself, looking out on vistas both urban and rural; in each direction the views are both fantastic and true, the inward glimpses as varied and complex as the outward landscapes. The largest, most masterful and most mysterious of these views are contained in the trilogy now completed, a trilogy in which life's very raw material is clothed in the rich and splendid fabrications of art.

In Wild Things, the angry young hero Max embarks on a fantasy sea voyage to a land of ferocious beasts. In this feral lair he stares down and tames the wild things, which are, of course, creatures of his own imaginings, avatars of Max's fractious disturbing feelings. In the second book, the cheerful, bumptious Mickey, awakened by noises in the night, embarks on a strange and wonderful journey through the air, first falling and then flying in a bread-dough plane of his own making that suggests Lindberg's Spirit of St. Louis. The subtext of In the Night Kitchen could be read as a paradigm of awakening sexuality -- another forbidden feeling -- and the nourishment of love, of the making and the uses of art in which the forbidden is transmuted, incorporated, and in part transcended.And in Outside Over There, the wistful and beautiful Ida -- the only truly beautiful Sendak heroine -- discovers that the baby sister she had momentarily ignored while playing on her wonder horn has been replaced by a changeling made of ice. The goblins -- at first faceless and shrouded, later revealed as babies themselves -- have snatched her for their goblin bride, a fate from which Ida, braving death must rescue her.

All Sendak's protagonists are plucky to one degree or another, though frightened by the trials they must endure to survive. The demons they find on their voyages of discovery into the self are always manageable. A friend asks, "You mean all your books have to do with terror and resolution?" Sendak, never reductive, as any analysis of his work must be, does not hesitate. "There is no resolution to terror," he says. "There may be reassurance."

The words that Maurice Sendak "got" in 1974 became the first few lines of Outside Over There: "When Papa was away at sea, and Mama in the arbor, Ida played her wonder horn to rock the baby still -- and never watched." They welled up one day and during the next two years -- Sendak is a very careful writer, grateful for every word that comes -- those mysteriously resonant, foreboding lines unfolded in the silence of his studio into the 351 words of the book. In the beginning is always the word. "I don't think in terms of pictures at all," he once told Virginia Haviland, head of the Children's Literature Division at the Library of Congress. "I find it's much more interesting and difficult to write and . . . as far as I'm aware, I think strictly in terms of words."

When the text is finally there, Sendak the writer removes his earplugs, turns on the Mozart (or the television; he is devoted to the soap opera All My Children, perhaps because of the title), enjoys the occasional company of friends, and becomes Sendak the artist. His goal, he told Selma Lanes for her full-length study (The Art of Maurice Sendak, Abrams, 1980), is finally to achieve something so simple and so put together -- so seamless -- that it looks as if you'd knocked it off in no time. tOne stitch showing and you've lost the game." He finished the paintings for Outside Over There on May 13, 1979, five years after the words first began to haunt him, three years after he had finished the text. They were years of dogged work, of depression, despair and elation, and for weeks afterward he had a recurring dream of having a baby which is taken from him. And, as he says, "I happen to love babies."

The words came in silence; they have their own tune. His brush, however, moves to music, particularly, in the late 18th-century setting of Outside Over There, to the music of Mozart, his inspiration, his guiding spirit, his deep rhythmic source. "I draw all the time to Mozart," he says, alluding to the fantasy sketches he begins and completes in time to shorter Mozart works. "Mozart dancing with Haydn, Mozart fighting with Constanze, Mozart doing whatever."

In an essay on Degas, Paul Valery says that Degas genius lay in his ability to follow the line, to continue the classical line without repeating or merely imitating it. Sendak freely acknowledges his debt to a multitude of painters: William Blake who was also, of course, a writer, George Stubbs, Winslow Homer, George Cruikshank, Daumier, Heinrich Hoffman, Randolph Caldecott, Ludwig Grimm, Chagall, Corot, Matisse, Boutet de Monvel; to the popular culture of his childhood: Walt Disney, King Kong Laurel and Hardy, Busby Berkeley, Winsor McCay; to writers: Henry James and Herman Melville, whose works he owns in first editions, Heinrich von Kleist, author of The Marquise of O, whose portrait appears on the wall of Ida's room, Rousseau; and to many composers besides Mozart: Haydn, Gluck, Britten, Janacek for whose opera, The Cunning Little Vixen, he designed the sets and costumes. (It opened at the New York City Opera last month.) The complete list of sources would be very long indeed. The homage is deliberate; the assimilation complete; the result distinctive, highly personal -- unique, in a word: a picture book like no other.

"Like an extravagant piece of poetry," Sendak writes in an introduction to a 50th-anniversary edition of Jean de Brunhoff's Babar books that Random House will publish later this year, "the interplay between few words and many pictures. . . is a difficult, exquisite and most easily collapsible form that few have mastered. . . Barbar is at the very heart of my conception of what turns a picture book into a work of art. The graphics are tightly linked to the deceptively loose [literary] style that is astounishing in its ease of expression. The pictures, rather than merely echoing the text, enrich and expand Babar's world . . . [and] the balanced emotional climate . . . is never allowed to go out of control."

Despite these cerebral influences, Sendak does not consider himself a thinker when he approaches his own work. About that, he thinks very little "if I think at all, and perhaps that's the best and safest thing that could have happened to me. I'm more stomach-directed than head-directed. The work comes out of these tempestuous fantasies that I don't think of as being in my head but somewhere in the direct middle of me, these urgent, all-consuming, thrilling feelings that have to be expressed."

After the performance of Really Rosie, after dinner had long since been consumed and the wine was low in the bottle, Sendak said that night in March in a sentence resonant with the tones of his admired Henry James, "How cleverly I have clothed the inner thing -- whatever that is." THE INNER THING

IT IS THE MIDDLE of April in southern Connecticut. The dogwood is not yet in bloom. The leaves of autumn and the winter's debris are just now being raked up. The first palest green of spring mists the lovely land. On a country lane hard by the New York border, a man is heading home from his daily walk with his three dogs, a walk that begins at 11:30 each morning and ends an hour or more later. There is no traffic on the road; there is not another person or another house in view. On this lane, across from a deep woods and behind a line of trees and shrubs, low stonewalls and rail fencing, stands the private domain of Maurice Sendak, who is just now ending his ritual walk.

"The world is so you have something to stand on," it says in A Hole Is to Dig (1952), Ruth Krauss' book of children's definitions that Sendak helped select and illustrate. This particular piece of it seems indeed a solid place to stand, as if it had been there -- as it has -- for generations, and will endure, providing and nurturing, for generations more. There is a hill topped by a grove of red pines and named Mr. Ida because the publisher's advance for Outside Over There paid for the transplanting of the big trees after the original white pines had been killed by the blight now threatening the countryside. Near the house -- a 1790 saltbox with two fieldstone wings from the 1920s -- there is an herb garden. Inside, the impression is all light and air, color and music and art: harmony. One thinks wistfully of the Age of Reason. Rousseau (whose Confessions Sendak is now reading with pleasure), Jefferson, and, yes, Mozart, come to mind. The state of nature is tamed here, subdued; the scale is human. One feels at home, or at least one would feel at home if home were like this.

Of course, the effort to maintain a pastoral idyll against the encroaching wild is considerable. One prefers not to think of the effort, but at least money is not a problem. (Sendak's books sell spectacularly well. Wild Things alone has sold more than 700,000 hardcover copies, and a paperback version for the school market almost 2 million. He has written and illustrated 11 books, and illustrated 78 others.) The landscape seems vaguely familiar, as if this hill, these dogs -- this spirit -- had been encountered before as, in literature if not in life, it has. It is Ida's, idealized to a degree, in Outside Over There.

But then, as Sendak says, "She is me." And she is also his sister, Natalie, nine years his senior and very beautiful. She is both of the above, and none, transmuted from whatever her original clay into Ida by the artist-alchemist for whom "flesh is so much mud redeemed by the gold of light," as Valery said of Rembrandt.

"I had such a consoling vision as a child -- an approach to an island," Sendak says, "It shows up in Wild Things but it's more appropriately represented in Outside Over There where, curiously, Ida ignores it." Not so curious, Ida though a young girl, 10 or 11, is a very wise child. "She starts out looking like a child but as she goes through her travail the experience registers on her face. She comes out about 112," with no need to look with longing on an idyllic child island, the ideal safe harbor, even if Mozart is playing there. "It's not really an island -- it's like a hill, a mountain," Sendak says. He gestures toward Mr. Ida. " There it is, that hill in back of the house. The ideal hill."

Such a landscape, such safe harbors, such wistful visions may seem far from the three-room flats in Brooklyn where Sendak spent his early years, the third and last, the frail child, the favored child -- or so he was told -- of Jewish immigrant parents. Although his father, whom he loved, used to say, "We are not put here to enjoy ourselves," Sendak's childhood was not desperately unhappy, nor very happy, either -- the sort of middling-to-miserable childhood with which many of us are familiar.

Maurice was born in 1928 to comfortably middle-class parents, his father a partner in a thriving dressmaking business in Manhattan. The Crash came the following year, his father lost everything, "and by the time I was conscious of living, we were poor." Maurice shared a bedroom with his sister and his adored brother Jack, five years older and "without any question my best friend and a devoted brother, an endless source of patience, of understanding.One of the happiest memories I have is of my brother sitting on my bed cutting something out for me -- shirt cardboard, paper -- making it move and amusing me, or drawing pictures on the window in winter, and I would be so delighted. I can see it now. My mother was different, more distant and shy with children. I didn't automatically run to her, I ran to my brother or my sister -- or my father, he was that kind of person. We were an intensely close family -- or at least we had the look of it -- even though endless volcanic tremors came out much later. And there was something else -- I don't know how to describe it -- the sense that we were a 'royal', like a family that had been dumped out of their original country. I don't know why I felt that. It must have come from my mother and father who had a great sense of specialness, which we of course picked up. Maybe all Jewish immigrants had that sense, a defense against their loneliness in a foreign land."

And then here was the terrible sense of doom that pervaded all Jewish families in the late 1930s, when their European relatives were disappearing one by one in Hitler's vast pogrom. Sendak remembers going to the Center Theater in Manhattan to see Pinocchio, "knowing somewhere inside me that I shouldn't be happy because something like a war was going on and my mother was crying, consumed with worry over relatives who were dying. My mother's whole job was to get her family out, and she did. My father dutifully helped her, and they all came to live in our three-room flat.But when it came time to get my father's family over, that was it, there was no way of getting out by then, so they were all killed. . . . I didn't want to think about it. I just wanted to get uptown to the Center Theater. I remember even the sky. It was gray, and I knew something very bad was happening and I should be ashamed of myself for so looking forward to a movie by Walt Disney. I remember these feelings so acutely, especially when they were related to movies or books," those twin objects of his pleasure, his desire, and his guilt.

Guilt is a might engine, and childhood, as Sendak says, "the most mysterious land that ever was." Without memory, it is forever lost; without that past, there is no future. Sendak remembers. Sometimes he thinks he remembers everything. At other times he says his memory of childhood events is no better than average. Both statements may be true. When he remembers and is able to summon and to render are the feelings of childhood. The facts -- the events he or any of us remember -- may be and usually are distorted, mistaken, or simply false. Feelings are always true, but it takes a particular kind of genius, a very special spirit to craft from those feelings, sensations, colors and dreams of childhood the forms that give them life. Sendak has that genius, and genius is a mystery, "an absolute mystery," says Ursula Nordstrom, the Harper & Row editor who first discovered him in F.A.O. Schwarz and who continues to work with him, though semi-retired. "It has been the greatest experience of my professional life to see him going deeper and deeper, getting better and better. And I've never stopped loving him, his openness, his generosity, and his great, great talent."

Yes, he is talented, and he knows it. He has a gift "but a gift is not salvation," as he puts it. "Look," he said one day after he'd finished a year's work on two operas and had no immediate project to dive into, though several possibilities, "I'm just an umemployed Jew from Brooklyn." That Maurice is a plucky kid and a very funny man -- a regular mensch, as they say where he comes from.