In 1936, Theodor Seuss Geisel was returning home to the United States from Germany aboard a luxury liner when a ferocious storm began to batter the ship. After passengers were ordered to return to their cabins, Geisel was plagued by memories of the doomed Titanic of 1912. To divert himself, he headed to the ship’s lounge, where he focused on scribbling out lines on ship stationery that were associated with more pleasant memories of his youth. The steady sound of the chugging engine gave him a sense of courage and the anapestic rhythm for his verse—which also matched the cadence of “’Twas the Night before Christmas.”

The images recalled what he had seen as an eight-year old watching a Fourth of July parade in 1912—including a float commemorating the Titanic—going down Mulberry Street in his hometown of Springfield, Massachussetts. But Geisel was already adding his own fantasies to childhood memory: “Chariot pulled by flying cat. Flying cat pulling Viking ship.” For the rest of the trip, Geisel remained fixated on the rhythm of the engine and the memories of Mulberry Street. His wife encouraged him to develop a story line combining the two. The result, published the following year, in 1937, was a book called And to Think That I Saw It on Mulberry Street.

That book, which came out eleven years after A.A. Milne introduced Winnie the Pooh to readers, would not rival the delicate intelligence or the imaginative nuance of the world’s most popular teddy bear. Nor did it have the psychological impact and mythical grandeur of the European fairy tales collected by the Brothers Grimm. But it marked the beginning of Geisel’s career as an extremely influential author of children’s books now known to generations of children and their parents around the world. This trajectory wasn’t immediate. The Cat in the Hat, for example, Geisel’s best-known book, wasn’t written until two decades later. But it and others like Green Eggs and Ham and Horton Hears a Who are among the most instantly recognizable and beloved titles of the 20th century—a love affair that shows no sign of fading after the first decade of the 21st. It was certainly not surprising that President Obama chose a Dr. Seuss book to be seen reading to his family in the White House garden last Easter.