This week marks the annual Banned Books Week celebration of intellectual freedom and the right to read. To mark the occasion, Annie Lionni, granddaughter of the acclaimed author-illustrator Leo Lionni, shares reflections on her grandfather’s socially conscious—and at times challenged—work, and the full story behind his debut picture book, Little Blue and Little Yellow.

My grandfather, Leo Lionni, wrote and illustrated 40 children’s books during his “retirement years.” His literary legacy includes four Caldecott Honors for excellence in illustration as well as dozens of other prizes, an elementary school curriculum based on his books described in Vivian Gussin Paley’s The Girl with the Brown Crayon, inclusions in best books lists, and countless praise from teachers, librarians, parents, and kids. I am frequently asked about what inspired Leo to write his stories.

The traditional story of how Leo came to write his first book for children involves my brother, Pippo, and me in 1959. At the time, Leo was an art director at Time Life, and he took us on the commuter train out of Grand Central Station in New York to spend the weekend with him and our grandmother, Nora, in Greenwich, Conn. He entertained us by tearing colored paper from a magazine that he had in his briefcase to create the story of Little Blue and Little Yellow. The positive response we gave to his story was enough to inspire him to recreate it with some construction paper in his studio at home. His friend, Fabio Coen, who later became an editor at Pantheon Books, saw the mock-up over the weekend and they decided to publish Little Blue and Little Yellow.

Over the years, the story of Little Blue and Little Yellow’s creation was told so many times, and in so many languages, that it took on a life of its own, morphing into a tale of two unruly kids on a train, and the grandfather desperate to keep them from bothering the other passengers. In his memoir Between Worlds, Leo contended that he was actually entertaining his fellow passengers in the process of keeping me and Pippo occupied. The more interesting story of where Little Blue and Little Yellow came from, and what inspired all of Leo’s later books, occurred to me only very recently.

Leo’s professional life was full and successful, and he was lauded with prestigious commissions. He worked as the art director of Fortune magazine, part of Henry Luce’s Time Life magazine empire, from 1948 until 1959. And in 1946 he designed the “Never Underestimate the Power of a Woman” campaign for Ladies Home Journal. He was one of the founders of the 1949 International Design Conference in Aspen—and interestingly enough, returned as a speaker at the 40th International Design Conference, which focused on children. He designed the prototype for Sports Illustrated in 1954, and his iconic design of the catalog for The Family of Man exhibit (Museum of Modern Art, 1955) is known by multiple generations. He maintained his own studio and had clients such as the American Cancer Society, the Container Corporation of America, and Olivetti. The 1950s were the pinnacle of his career as a graphic designer.

During the mid-cold war climate, plans were underway for a United States pavilion at the 1958 Brussels World’s Fair. Members of the United States delegation were concerned that the U.S. would be heavily criticized for our segregation policies and other restrictive national issues—such as the Little Rock Crisis in 1957, in, which nine students in Little Rock, Ark., had been prevented from attending high school until President Eisenhower sent in federal troops. The world was watching us and taking note of our domestic problems and the way in which we handled them.

It was decided that, in addition to our regular pavilion, the U.S. would create a small pavilion called “Unfinished Business.” The theory was that, by publically disclosing our flaws, we would sidestep some anticipated criticism from other countries; specifically, Russia. Focus groups and studies were set up to determine how effective the plan would be in diverting the anticipated criticism. The project had been conceived, and supported, by Henry Luce, in collaboration with the State Department. While working for Luce at Fortune, Leo was asked to design the little pavilion, which was to be installed next to the main United States pavilion. The pavilion was composed of three sections: the problems, the progress, and the goals, each contained within its own physical structure; one leading to the next. The topics included segregation, urban blight, and the wasting of natural resources.

In the last section, which portrayed the goal or ideal solution, Leo included a large photograph of a racially mixed group of children playing Ring Around the Rosy. There was a fair amount of concern among southern senators as the opening of the Fair approached. They felt that we were exposing private domestic issues in a way that put the southern states in a bad light. A flurry of letters and telegrams between U.S. politicians, including Georgia’s Senator Herman Talmadge, South Carolina’s Senator Strom Thurmond, and the State Department illustrate the opposition that was building against the entire concept of the pavilion.

Jack Masey, a designer with the United States Information Agency, responsible for managing the projects that the State Department requisitioned, and writer Conway Lloyd Morgan reproduced a telegram written by Herman Talmadge in their book, Cold War Confrontations. In it, Talmadge is shown to distance his state from the official position that segregation should be banned, writing, “It is obvious… that the Fortune exhibits will present only one side of this issue and will seek to show in the worst possible light those states and regions of our country in which segregated society has proved to be in the best interests of all races concerned.” Despite these objections, “Unfinished Business” opened to the public. Among various efforts to change the tone of the pavilion, a sign was posted below the image of the children playing Ring Around the Rosy, asserting that it did not represent the goals of the United States.

Within a matter of weeks, “Unfinished Business” was shut down. A scapegoat was needed to justify the closure of the pavilion, so Leo was blamed for bad design. It was clear from exit surveys, however, that the pavilion was very well received by visitors from all over the world. Instead, it was the skirmish between our own senators and the State Department that caused the closure. Several articles have been written in recent years concerning the pavilion and the controversy surrounding its brief life at the fair. Historians— particularly those specializing in the importance of graphic design as an influential force in popular thought—have included the story of “Unfinished Business” in their writings. Leo, himself, kept a close eye on the events that followed concerning the American Pavilion; he was back in New York, but his thoughts were still in Brussels. The illustrator Saul Steinberg had been commissioned to include a 230-foot mural depicting American life. When the Fair closed, the eight-panel mural was cut up into 84 boards and stored. Leo wrote to Steinberg, “I hope that they will be housed properly after the expo. I’ll raise bloody hell if they don’t.”

In July of 2014, I received an email from Jack Masey’s wife, Beverly Payeff-Masey, about an image in Jack and Conway’s book Cold War Confrontations. The image was one of Leo’s photos, taken in the very earliest days of the Brussels World’s Fair, before “Unfinished Business” was shut down. (There is, in fact, a series of 57 such photos that Leo had taken.) Payeff-Masey described the last image in the pavilion as “a group of children playing ‘ring a ring o’ roses.’ ” I knew I had heard of a game with that same name—but where?

Later that night, I tossed and turned until I finally got up to check the date of the Brussels World’s Fair. It was 1958; the year before Little Blue and Little Yellow was published. I picked up a copy of the picture book and turned to a page that depicts a group of characters playing “ring a ring o’ roses.” The layout of the page is just like the image of the kids playing Ring Around the Rosy in the “Unfinished Business” pavilion.

Leo’s exhibit was edited and then entirely cut from the Brussels World’s Fair, but the following year, he began the first of what eventually grew to be 40 books for children, all allegories, talking about a more perfect world. All of Leo’s stories are about communities. They all contain a problem, and they all look for solutions. A few of the problems he addressed in his books—like many of our own here in the United States—do not get solved in his stories, but most of them do. Like the pavilion, his stories are as much about the process as anything: identify the problem; deal with the problem; rejoice that the problem has been solved.

Here are just a few of the stories that Leo told about solving problems in the worlds of his creatures. Swimmy (1963) choreographs his friends into an image of a large fish to scare away the tuna that threatens them. Geraldine of Geraldine, the Music Mouse (1979) helps her brethren to hear music. Tico, from Tico and the Golden Wings (1964), uses his golden feathers to help those in need. Mr. McMouse (1992) saves his friend by outwitting the threatening cat. Nicolas, from Nicolas, Where Have You Been? (1987), is a mouse who is nurtured by birds, as if he were one of their own. Fish Is Fish (1970) is about point of view. Frederick (1967) brings the sustenance of imagery and poetry to his community of cold and hungry mice. And the caterpillar in The Alphabet Tree (1968) brings an important antiwar message to the President.

The censorship Leo grappled with in the closure of the Brussels pavilion was not to be his last. There have been several occasions in which Leo’s stories were banned in one place or another because they were deemed threatening to the status quo. As recently as July 2015, three Lionni titles, including Little Blue and Little Yellow, Swimmy, and Pezzettino, appeared on a list of books that are being banned in schools by the mayor of Venice, Italy, because they were deemed potentially threatening to traditional families. These books are about community, tolerance, and ingenuity. They are timeless, as apparently, are the problems they address.

While the anecdote of creating Little Blue and Little Yellow on the train was true, that was the unimportant story. I’ve realized that the creation of Leo’s books had little to do with entertaining Pippo and me on the train. Leo’s stories were his way of finishing his business and striving to make a better world.

Random House Children’s Books has kicked off a yearlong celebration of Lionni’s work, tied to the 50th anniversary of Frederick. Read more here.