THE JOYOUS FELLOWSHIP of Jonathan Cott and children's books came about as a kind of happy accident. In London in the late '60s, bored with the modern British poetry he had gone to England to study and oppressed with the sense that he had been in school more or less forever, Cott was introduced to George MacDonald's writing for children by an "empathetic friend." He followed that lead into wider realms of children's literature, where, to his relief, he found his literary satiety lifted. Suddenly, he writes, he was able to read with intensity again: "Words seemed to glisten and sparkle, like the light on clear mountain streams." Children's books had brought him "renewal and awakening."

When that encounter took place, children's literature gained as much as did Jonathan Cott. In the 15 or so years since his rediscovery of the literature of childhood, Cott has edited and written widely on a variety of topics without losing either interest in children's books or the intensity of response they evoke in him. In Jonathan Cott, children's books have acquired as literate, as receptive, and as articulate a spokesman as the most exacting devotee of the literature could wish.

Pipers at the Gates of Dawn brings together a collection of seven interviews Cott has conducted with outstanding contributors to the field of children's literature. Here are conversations with Maurice Sendak, unquestionably the most influential creator of picture books in our time; William Steig, New Yorker cartoonist who is also author and illustrator of a highly individual body of work for children; Astrid Lindgren, Swedish author of the incomparable Pippi Longstocking books; P.L. Travers, creator of the equally incomparable Mary Poppins; Chinua Achebe, Nigerian novelist and author of stories and fables for children; and Theodore Geisel, much better known to the world as Dr. Seuss.

The book also includes (it is my own favorite) a wonderfully enlightening profile of Iona and Peter Opie, whose astonishing scholarship has thrown light on a hitherto all but invisible subject, the lore and language of children themselves--the age-old, ever-new oral lore which is common parlance among children, and almost wholly lost to adults. In this piece, finished shortly before Peter Opie's death in 1982, Cott shows how two meticulous and original scholars work to capture the most elusive of material, and how they find echoes of the chants, rhymes, and games they record in the schoolyard today in the chants, rhymes, and games alluded to in Chaucer, Spenser, Shakespeare, or any of hundreds of other literary sources. Cott also makes it clear that the record-keeping, however voluminous, is only the lesser half of the method. Far more important is the intelligence and sensitivity the Opies have always brought to their chosen task, whether they are researching children's play, nursery rhymes, or fairy tales. Like all the best scholarship, the Opies' work is infinitely more than its data; it draws together past and present, change and continuity, illuminating both and demonstrating the unsuspected glories of the commonplace.

Each of these essays will find its audience, for each is fresh and informative. Cott must be the ideal interviewer. He comes to his subjects so steeped in their work that the ensuing conversation is much more nearly a dialogue than an interview; a dialogue, moreover, full of nuance and connection, in which Cott and his subject together explore the meaning and the sources of the author's work. Here is Cott tracking a source of And To Think That I Saw It On Mulberry Street with Theodore Geisel, who wrote it. Cott: "I wanted to bring up . . . the possibility of Mulberry Street and Goethe's 'The Erl-King' being somewhat similar." Geisel responds by quoting, in German, the first two lines of Goethe's poem and adding, "I was brought up in a German-speaking home . . . I learned 'The Erl-King' . . . when I was still in high school. It could tie up . . . I've never thought of it before."

The revelation here is not that Cott found a parallel between Goethe's poem and Geisel's, but that the connection was real and unrecognized in Geisel's mind. Cott's identification of an unremembered source behind a literary work, even so playful a work as Geisel's, illustrates exactly the special function of a thoroughly literate critic.

Throughout his long interview with P.L. Travers, Cott and Travers exchange quotations from a dizzying range of sources--Blake, Keats, Rilke, the Gnostic Acts of John, and D.H. Lawrence, to name only a few. At one point, Travers recalls a line from Mary Poppins:' "The shadow is the outside of your inside," and Cott returns with Jesus' words on the coming of the Kingdom: "When the two shall be one, the outside like the inside, the male with the female neither male nor female." Whereupon Travers exclaims, "You're really teaching me my book," and Cott replies, "Your book taught me about your book." It is a passage which captures well the tone and the achievement of Cott's interviewing. Lucky the authors who find such a critic. And lucky the readers who find essays as intelligent, as penetrating as these to take them nearer the subtle beauties and the unexpected complexities of the great books for children.

Pipers is an attractively produced volume, illustrated with photographs of the authors interviewed and with black and white reproductions of illustrations from their books.