Video games and movies aren’t the only media to contain inside jokes, allusions, and puzzles: some literary giants are in on the act, too. Whether it’s an odd quotation, invented place, or mysterious pattern, these tidbits—which can escape detection on a first reading—often have a special significance for the author. Eagle-eyed readers have searched for and shared these literary Easter eggs, and we’ve rounded up eight sneaky and surprising examples below.

1. An Acrostic Poem // Lewis Carroll's Through the Looking-Glass

The huge success of Alice in Wonderland and Through the Looking-Glass meant that author Lewis Carroll was always being asked who the main character of Alice was based on. Carroll was generally coy about giving an answer, although many suggested that she was based on family friend Alice Liddell. It later emerged that he had first invented the story while amusing the Liddell girls on a boat trip down a river. Attentive readers soon noticed Carroll was not so coy after all—he had included an acrostic poem at the end of Through the Looking-Glass entitled "A Boat Beneath a Sunny Sky," in which the first letter of every line spells out “Alice Pleasance Liddell."

2. A Fake Literary Feud // Bevis Hillier's John Betjeman: The Biography

Bevis Hillier, the official biographer of poet John Betjeman, took the Easter egg one step further when he concocted an elaborate hoax to fool rival Betjeman biographer A.N. Wilson. Hillier forged a love letter from Betjeman to a work colleague, which found its way into Wilson’s hands. Thinking he had a scoop, Wilson published the letter in his book. Unfortunately, journalists reviewing Wilson’s book soon noticed that the first letter of each sentence in the forged letter spelled out “A. N. Wilson is a sh*t,” and Hillier later revealed he had orchestrated the hoax in revenge for a terrible review Wilson had written of his Betjeman biography.

3. A Character from a Previous Novel // F. Scott Fitzgerald's The Great Gatsby

In The Great Gatsby, F. Scott Fitzgerald includes an epigraph (a quotation from another writer at the start of a book or chapter) by Thomas Parke D'Invilliers:

"Then wear the gold hat, if that will move her;
If you can bounce high, bounce for her too,
Till she cry 'Lover, gold-hatted, high-bouncing lover,
I must have you!'"
– Thomas Parke D’Invilliers

So far, so normal—except that Thomas Parke D'Invilliers was character invented by Fitzgerald. D’Invilliers appears as an “awful highbrow” poet and friend of Amory Blaine in This Side of Paradise, which was published in 1920, five years before The Great Gatsby. Fitzgerald never publicly admitted authoring the epigraph, despite the fact that numerous people asked him for details of D’Invilliers so they might seek permission to use the quote themselves. However, Fitzgerald’s authorship was confirmed when a rare signed and inscribed copy of The Great Gatsby came to light in which Fitzgerald finally claims the epigraph as his own—by scribbling the word “myself” below the imaginary poet’s name.

4. A Secret Note to a Significant Other // Margaret Atwood's The Handmaid's Tale

In Margaret Atwood’s dystopian novel The Handmaid’s Tale, fans puzzled over the significance of some graffiti that main character Offred sees etched into a desk. The letters read “M. loves G., 1972.” Wily readers later noted that Atwood (M) had started a lifelong relationship with fellow author Graeme Gibson (G) in 1972.

5. An Epigram About the Kennedy Assassination // Cordwainer Smith's On The Storm Planet

Cordwainer Smith was the pseudonym used by East Asia scholar and psychological warfare expert Paul Linebarger when he wrote science fiction novels. In his 1965 novella On The Storm Planet (often included in the collection Quest of the Three Worlds), Smith added references to the 1963 assassination of President John F. Kennedy using an epigram inserted into the text. The first letter of each word in one seemingly-normal string of sentences spells out “Kennedy shot,” and a few pages later another epigram adds “Oswald shot too.” The hidden message does not disrupt the flow of the writing, making the Easter egg even harder to spot.

6. Runes Hiding a Message // J. R. R. Tolkien's The Fellowship of the Ring

J. R. R. Tolkien was a language professor at Oxford University, and his love of words and language inspired his novels. On the original title page of The Fellowship of the Ring, the first book of The Lord of the Rings, Tolkien inscribed two of his invented writing systems in the borders, which at first glance appear to be mere pretty decoration. However, some clever fans have since translated the lettering to reveal his hidden message. The full translation reads: “The Lord of the Rings translated from the Red Book of Westmarch by John Ronald Reuel Tolkien. Herein is set forth the history of the War of the Ring and the Return of the King as seen by the Hobbits.”

7. A Foreshadowed Protagonist // Stephen King's IT

Stephen King is well-known for including numerous Easter eggs in his novels, often linking characters and places from one book to the next, creating a complex web of allusions and references. One of King’s most random Easter eggs is included in his novel IT (1986), in which one of the tormented children is Eddie Kaspbrak, who King casually mentions lives next door to Paul Sheldon and his family. Paul Sheldon then turns up as the unfortunate protagonist in King's novel Misery (1987) just a few years later.

8. A College Doppelganger // Bret Easton Ellis's Less Than Zero

Bret Easton Ellis reimagined his own alma mater, Bennington College in Vermont, a number of times in his books, renaming it Camden College. Known in the 1980s for being one of the most expensive American schools, Bennington was also famed for its openness to experimentation and, some say, debauchery—elements Ellis used in his plots. "Camden College" first appears in Less Than Zero (1985), but also crops up in The Rules of Attraction (1987), American Psycho (1991), The Informers (1994), and Glamorama (1998). Strangely, Ellis isn’t the only one to use “Camden College” in his books—fellow Bennington alum Jill Eisenstadt (in From Rockaway, 1987) and Jonathan Lethem (in The Fortress of Solitude, 2003) also use Camden as a cipher for Bennington in their novels. Nor do the Bennington doubles end there: Donna Tartt, another classmate of Ellis, also uses a Bennington-esque college in The Secret History (1992), but she names it Hampden.