Like square caps and billowing gowns, Dr. Seuss's Oh, the Places You’ll Go! has become synonymous with graduation ceremonies. Every year, thousands of copies of the book are handed out to a fresh crop of diploma-carriers. But there are a few key things that you might not know about the 1990 Dr. Seuss classic.

1. The book’s title was inspired by an Ivy League pleasantry.

Theodor Seuss Geisel (a.k.a. Dr. Seuss) earned a bachelor’s degree from Dartmouth College in 1925. While enrolled there, his classmates liked to exchange an optimistic greeting that became popular on-campus: "Oh, the places you’ll go!" one pupil would say, to which the other party would reply, "The people you’ll meet!" Geisel’s book immortalizes one half of this little salutation.

2. Ted Geisel fretted about the tone of Oh, the Places You’ll Go!.

“Initially, Ted worried that Oh, the Places You’ll Go! sounded ‘preachy,’” Geisel’s second wife, Audrey, once shared. “I assured him it wasn’t. I think he was intending it to be the summation of his own life. He was taking everything he knew and putting it into the life-voyage of this particular little boy.”

3. Some of the book’s illustrations had been in Geisel’s head for years.

Cathy Goldsmith, Geisel’s longtime art director, regularly visited his home in La Jolla, California, and helped him color-code the illustrations for Oh, the Places You’ll Go! According to Goldsmith, Geisel “said that some of the images in the book had been in his head for years and he’d never found a way to use them before.” She later found out that Architectural Digest had taken some photos of the author’s home for a 1978 article. One of their pictures shows a wall full of original sketches—including two that resurfaced in Oh, the Places You’ll Go! more than 10 years later.

4. The early reviews of Oh, the Places You’ll Go! were mixed.

The Scripps Howard News Service’s Frederic Koeppel called Oh, the Places You’ll Go! "slack and unimaginative" and said that the illustrations were just "pale imitations of [Seuss’s] best work." The New York Review of Books was similarly unimpressed, dismissing the book as "the yuppie dream—or nightmare—of 1990 in cartoon form." The New York Times's critic Diane Manuel felt that it was “uncharacteristically tame” for a Dr. Seuss offering.

Other reviewers were more enthusiastic: Writing for the Gannet News Service, Susan Stark proclaimed that Oh, the Places You’ll Go! had "the greatest thematic breadth of any book in the extraordinary Seuss canon."

5. An animated film version of Oh, the Places You’ll Go! died during development.

Shortly after the book’s publication, Tristar Pictures expressed an interest in adapting Oh, the Places You’ll Go! as an animated movie. Geisel threw himself into the project, discussing the finer points with producers and going over potential scripts. Unfortunately, the film died in development. But if it had been completed, it would have been the first feature-length movie to be based on a Dr. Seuss story. Instead, that honor went to Ron Howard’s live-action How the Grinch Stole Christmas (2000), starring Jim Carrey.

6. Oh, the Places You’ll Go! was the last Dr. Seuss book to be published during Geisel’s lifetime.

On September 24, 1991, Theodor Seuss Geisel died peacefully in his sleep at the age of 87. Oh, The Places You’ll Go! had hit arrived in bookstores on January 22, 1990. Since then, a few of Seuss’s other stories have been published post-mortem, including the rediscovered lark Which Pet Should I Get?

7. Oh, the Places You’ll Go! is Dr. Seuss’s bestselling book.

In 2018 alone, Oh, the Places You’ll Go! sold 800,000 copies. Overall, more than 12.5 million copies have been purchased, making this Dr. Seuss’s best-selling book. (The runners-up list includes Green Eggs and Ham, The Cat in the Hat, and How the Grinch Stole Christmas.) Oh, the Places You’ll Go! is a popular gift for newly-minted high school and college grads—so its sales reliably increase every spring, when graduation season rolls around.

8. Oh, the Places You’ll Go! has been read aloud by the likes of John Lithgow and J.K. Simmons.

John Lithgow may be best known for his Emmy-winning performance as Dick Solomon on the sci-fi sitcom, 3rd Rock from the Sun. But the two-time Oscar nominee has also narrated the audiobook versions of numerous Dr. Seuss books, including Oh, the Places You’ll Go! Not to be outdone, J.K. Simmons—who won a Best Supporting Actor Oscar in 2015 for Whiplash—helped Farmers Insurance celebrate Geisel’s 115th birthday on March 2, 2019 by reciting the children’s classic out loud, along with a brand-new, Seuss-inspired poem called “The More That You See” (which tied into a Farmers advertising campaign).

9. Oh, the Places You’ll Go! has been frequently parodied.

Looking for some tongue-in cheek advice about doomed startups and trendy office buildings? Read Oh, the Meetings You’ll Go To!, a 2017 spoof from Penguin Random House that’s written under the pseudonym “Dr. Suits.” Then there’s Antonio Carter’s profanity-riddled sendup Oh, the S--t You Don’t Know!—and Oh, the Places You’ll Eff Up! A Parody for Your Twenties by Josh Miller and Patrick Casey. More recently, ComicMix unleashed Oh, the Places You’ll Boldly Go!, a Star Trek-inspired picture book with a distinct Seussian flair. (People have been satirizing Dr. Seuss for quite some time; in the 1990s, the National Wood Flooring Association released a pro-logging children’s book called The Truax as a direct rebuttal to The Lorax.)

10. The entire text of Oh, the Places You’ll Go! is engraved on a book-shaped statue at the Dr. Seuss Memorial Sculpture Garden.

Springfield, Massachusetts, was Geisel’s birthplace and the city takes great pride in its native son, hence the creation of the Dr. Seuss Memorial Sculpture Garden in 2002. Frolicking around the book are full-sized bronze statues of the Grinch, the Cat in the Hat, and Dr. Seuss himself.

"I chose to put this book in the Memorial because it is Ted’s last book ... It is Ted’s farewell," sculptor Lark Grey Diamond-Cates, who also happens to be Geisel’s stepdaughter, said of the memorial. "Over the years it has given me deep pleasure whenever I see someone standing in front of this book quietly, thoughtfully, reading Ted’s parting words."