The miraculous moment when line and color quicken into art occurs as gladly in children’s picture books as in medieval Psalters. A Francophone elephant in a green suit belongs to the natural history of make-believe no less than the griffins and unicorns of ancient bestiaries or manuscript marginalia. So, the Morgan Library is a fitting repository for the surviving drafts of text and illustrations for the creation of Babar, the paterfamilias of a classic modern bedtime story.

“Drawing Babar: Early Drafts and Watercolors” includes roughly 175 preliminary pages for the first book by each of Babar’s two authors: Jean de Brunhoff and, later, his son Laurent. A delightful and instructive exhibition, it offers a tutorial in the genesis of a picture book that enchants, in large measure, because it does not draw down to children. The illustrations — particularly Jean’s — are not ornaments to the text but co-conspirators with it.

Babar, an orphaned baby elephant, flees the African jungle and heads for Paris where he acquires — what else? — a French flair for genteel living and a taste for the finer things. Later, he returns to the elephant realm to establish Celesteville, bringing with him joie de vivre, Gallic civility, and style. Pachyderm natives crown him king, don Western clothes, and start speaking French.

The initial story line has earned predictable scowls from pecksniffs alert to signs of colonial paternalism. But as mothers and fathers know, bonheur does not come naturally. A mission to civilize is every parent’s binding duty. Babar says it himself: “Family life is hard.” His gentility and imperial sensibilities have been an asset in the nursery for nearly 80 years.

Babar and his progress were a family affair that began one bedtime in 1930. Cécile de Brunhoff tucked in her two sons — 5-year-old Laurent and his younger brother Mathieu (the third, Thierry, was not yet born) — with an invented tale of a nameless baby elephant left to make his picaresque way as best he could. Enthralled, the boys lobbied their father to draw pictures for it.

Jean was an accomplished painter who had never written or illustrated a book before, but was game to try. He gave his protagonist a name, expanded the tale, and illustrated it with a series of watercolors. Such domestic efforts, common enough, rarely find a larger audience, but this was an uncommon family. Jean’s father had previously produced an illustrated version of the Bible. Jean’s brother-in-law, director of a French fashion magazine, and his brother, editor of Paris Vogue, steered the book to publication. It appeared in 1931 as “Histoire de Babar, le petite éléphant.”

The tale, told in simple prose and clear, affectionate images, immediately won French hearts and was translated into English two years later. Jean added six more to the series, before he died in 1937. Laurent began writing and illustrating Babar books himself in 1946, and has continued ever since. Also a painter, he had studied under his father’s former teacher, Othon Friesz, and exhibited briefly before attempting his own Babar book, “Babar et ce coquin d’Arthur” (Babar and the Rascal Arthur). Thirty-six successors followed, the latest just this year.

Part purchase, part gift from the de Brunhoff sons, the exhibition is effectively arranged to emphasize the process of creating, developing, and carrying to completion a visually conceived chronicle. It traces the different methods of the two men who, working a generation apart, sustained a narrative art that appeared seamless in its linearity, color sense, and dramatic simplicity.

Jean’s original pictures, handwritten text, and mock-ups indicate that he approached all aspects of his book — text layout, illustrations, page design — as a unified whole. Even the end papers and the visual disposition of the text, created in a schoolboy’s round-hand script, excited his concern. His final, printer-ready illustrations are formally matted in dark frames and placed side by side with his rehearsals and alterations. These are floated in white frames, an illuminating comparison. The tale and its dramatis personae evolve under your eye.

Laurent separated text and image, beginning with loose, sketchy color washes over faint pencil lines that felt out their place on the page. Figures were defined later, often with black lines laid directly over the watercolor. It is these lines that are the crucial link between the work of father and son. Laurent absorbed the character of his father’s line as if it was his own. He worked his way to the point where his father began.

The years between the mid-1930s and the end of World War II were glory days for children’s books. A dignified elephant king, who ruled well and asserted the abiding goodness of home, struck just the right note for a wounded era. In Babardom, obstacles are overcome, conflicts are resolved, and good hearts prevail. A grievous world can wait; meantime, familial love is a shelter in unsteady times.

The Morgan’s exhibition is timed to coincide with publication of the latest in the series, Laurent’s “Babar’s U.S.A.,” a disappointing sequel. The enveloping charm of hand-drawn wash settings gives way to the mechanical imposition of cartoon elephants on brash color photos of hackneyed tourist spots such as Nashville, Graceland, Disneyland, and Hollywood. The book crosses the threshold of make-believe into a pseudo-reality better geared to framing Roger Rabbit in Los Angeles.

Children’s literature changes with the culture around it. Imperial France is extinct; Laurent lives now in America, and Babar risks becoming a vulgarian consumer who airlifts cell phones, iPods, and video games to the natives of Celesteville. The sweet moments of Babar’s dual beginning — first with Jean, again with Laurent — serve as epitaph for a vanishing culture of childhood.

Connoisseurs of children’s literature, and picture book design, lovers of storytelling, and Babar buffs will want the catalog with its fine essays by curators Christine Nelson and Adam Gopnik.

Until January 4 (225 Madison Ave. at 36th Street, 212-685-0008).