Humpty Dumpty was Lewis Carroll’s first annotator, but he wouldn’t be the last. When Alice meets Humpty, about halfway into Through the Looking-Glass and What Alice Found There, he’s fairly obnoxious, rudely telling her she has “no more sense than a baby.” When she admits to not knowing what he means by the phrase “There’s glory for you!,” he replies, “Of course you don’t—till I tell you.” Nevertheless, Alice courteously asks him for help in deciphering a strange poem she has encountered earlier in her travels:

“You seem very clever at explaining words, sir,” said Alice. “Would you kindly tell me the meaning of the poem called ‘Jabberwocky?’ ”

“Let’s hear it,” said Humpty Dumpty. “I can explain all the poems that were ever invented—and a good many that haven’t been invented yet.”

 In the ensuing pages, he offers glosses on puzzling words like slithy (“‘lithe and slimy’…You see it’s like a portmanteau—there are two meanings packed up into one word”) and outgrabe (“something between bellowing and whistling, with a kind of sneeze in the middle”).

Some might describe Humpty’s patronizing, pompous tone as mansplaining (or maybe, given the source, “eggsplaining”). But plenty of readers will understand the urge to provide definitions and interpretations as well as Alice’s desire to hear them. In recent years, more and more of us are reading annotated editions of our favorite books—The Annotated Wuthering Heights, The Annotated Lolita, The Annotated Anne of Green Gables—as well as posting on sites like, which claims to host more than a million annotated texts, and sharing notes and highlights on Kindle. Never before has there been so much activity in the margins of culture.

What makes a good annotator? It’s some combination, apparently, of excess and restraint: an instinct for when to tell us more than we need to know (or more than we knew there was to know) balanced with a refusal to bore us. The obvious is, obviously, out: Most readers of Carroll probably won’t need to be told what croquet is, for instance. More difficult is distinguishing between an alluring obscurity and a total waste of time. Not all rabbit holes are worth going down.

This is a question that Genius, whose slightly megalomaniacal slogan is “Annotate the world,” is still grappling with. The site launched in 2009 as Rap Genius, devoted to the explication of rap lyrics. These origins have been the occasion for a lot of dismissive jokes, but it makes perfect sense that an annotation web site would orient itself toward such a dense, allusive art form. Rap, like Carroll’s writing, is full of mysteries that cry out for explanation: Think of the Wu-Tang Clan’s mix of Five Percenter lingo, references to kung fu films, and drug trade slang, for instance, or Kendrick Lamar’s brash collages of personal confession and black history. It’s also, as with children’s literature, an often disrespected genre that inspires a passionate devotion in highly intelligent people who are ready to sound the depths of their pleasures in order to prove the skeptics wrong.

Rap remains Genius’s bread and butter, but last year, after receiving $40 million in venture capital funding from Cleveland Cavaliers owner Dan Gilbert, the company shortened its name and impressed the media world by hiring cultural critic Sasha Frere-Jones away from The New Yorker to be its executive editor. (Frere-Jones has since departed to work at the Los Angeles Times.) Recently, Genius has been making an ambitious effort to expand into areas beyond music: There is Lit Genius, News Genius, History Genius, Law Genius, and so on. The company has supported “Genius Teaching Fellowships” for academics and brought in such authors as Junot Díaz, Sheila Heti, and Jeff VanderMeer, alongside Eminem, Nas, and A$AP Rocky, as “verified artists.” Most recently, it has entered the political arena, collaborating with Hillary Clinton’s staff to offer an annotated version of her campaign kickoff speech.

Genius, like Wikipedia, is crowd-sourced: It lets anyone contribute “tates” (short for annotations), which can then be rated by other users. “Texts on Genius are living documents,” the site’s About page reads. “Over time, they transform into definitive guides as people just like you from around the world add bits of knowledge to them.” Below this grandiloquent ad copy, an animated GIF shows the steady evolution of the page for Carroll’s “Jabberwocky” as users layer on multiple annotations. It’s an impressive display. But the claim that it reflects Genius’s “accretive magic in action” is a little weak, given that, last I checked, 13 out of the 27 annotations on the “Jabberwocky” page include direct quotations from a single source: Martin Gardner’s The Annotated Alice.

When it comes to explanations of Carroll’s books, no one has yet improved on the work of Gardner. One of the twentieth century’s great polymaths, he was born in Tulsa, Oklahoma, in 1914, and attended the University of Chicago, where he studied philosophy with Rudolf Carnap and writing with Thornton Wilder. For years he wrote the beloved Mathematical Games column for Scientific American and published books on everything from how-to guides on close-up card magic to a biography of Christian Science founder Mary Baker Eddy.

Gardner was brilliant but, unlike Humpty Dumpty, he was humble. Robert Weil, Gardner’s editor in the final decades of his life (he died in 2010), told me he remembers him as “an intensely modest and sweet man…He was like a kid plucked out of The Wizard of Oz…The prairie wonderment and innocence never left him, even in his nineties.” But he also had an impish sense of humor (he once panned one of his own books in The New York Review of Books writing under the pseudonym George Groth) and a hyper-logical intelligence: both important prerequisites for understanding the mind of Charles Dodgson, the Oxford mathematician better known as Lewis Carroll, who spent his spare time writing nonsense epics for children.

It was Gardner’s idea that the Alice books should be annotated; he first asked the great logician Bertrand Russell to write the notes, but when Russell declined, Gardner stepped in to do the job himself. Children’s literature was not a respectable object of scholarly attention at that time, and Gardner’s introduction opens somewhat apologetically. He concedes that “there is something preposterous about an annotated Alice” before offering a defense of the undertaking: “No joke is funny unless you see the point of it, and sometimes a point has to be explained.” And Carroll, he reminds us, was a uniquely hermetic writer: 

In the case of Alice we are dealing with a very curious, complicated kind of nonsense, written for British readers of another century, and we need to know a great many things that are not part of the text if we wish to capture its full wit and flavor. It is even worse than that, for some of Carroll’s jokes could be understood only by residents of Oxford, and other jokes, still more private, could be understood only by the lovely daughters of Dean Liddell.

What follows does far more than explain Carroll’s jokes (though it does that, too). Gardner’s marginal text is encyclopedic, gathering together a small mountain of biographical and bibliographical information on Carroll with much else besides. At times it functions as a field guide to Victorian England, describing such unfamiliar items as “bathing machines” (“small individual locker rooms on wheels”) and “comfits” (“hard sweetmeats made by preserving dried fruits or seeds with sugar and covering them with a thin coating of syrup”). Gardner tells us that when Carroll was writing, “there was considerable popular speculation about what would happen if one fell through a hole that went straight through the center of the earth.” He diagrams every movement made by characters in Through the Looking-Glass, whose narrative Carroll carefully modeled on a game of chess. He points out allusions to the Alice books by later authors (T.S. Eliot in “Burnt Norton,” James Joyce throughout Finnegans Wake) and provides the originals of the mostly forgotten songs and poems that Carroll parodied. We learn that the phrase “mad as a hatter” probably arose because “the mercury used in curing felt...was a common cause of mercury poisoning,” and that “Victorian children actually had dormice as pets, keeping them in old teapots filled with grass or hay.”

Gardner was a philosopher by training, and his most intricate and idiosyncratic annotations tend to reflect this. When Tweedledee and Tweedledum inform Alice that she’s “only a sort of thing” being dreamed of by the slumbering Red King, Gardner notes that it “plunges poor Alice into grim metaphysical waters. The Tweedle brothers defend Bishop Berkeley’s view that all material objects, including ourselves, are only ‘sorts of things’ in the mind of God. Alice takes the commonsense position of Samuel Johnson, who supposed that he refuted Berkeley by kicking a large stone.” He makes a convincing case that Carroll was fascinated by symmetry and left-right reversals, as was Gardner himself (in 1964, he published The Ambidextrous Universe, an entire book on the subject). One of his strangest and most entertaining digressions involves Alice’s suspicion that “Looking-glass milk isn’t good to drink,” which he delightedly confirms, based on the latest discoveries in particle physics (circa 1960): “It now appears likely that particles and their antiparticles (that is, identical particles with opposite charges) are...nothing more than mirror—image forms of the same structure,” he writes. “If this is true, then looking-glass milk would be composed of ‘anti-matter,’ which would not even be drinkable by Alice; both milk and Alice would explode as soon as they came in contact.”

The Annotated Alice was an unlikely best-seller. It has now been translated into Italian, Japanese, Russian, and Hebrew, among other languages; in 2005 Gardner estimated it had sold more than a million copies worldwide. Besides catalyzing academic interest in Alice, it helped to secure Carroll’s reputation with the reading public and to reassert—nearly a decade after Disney’s watered-down animated adaptation of Alice in Wonderland—the intricacy and specificity of his imagination.

Just as importantly, though, The Annotated Alice gave rise to a new popular genre. Though scholarly annotations, especially of biblical or ancient texts, had been around for millennia, annotations of modern books for popular audiences were a novelty in the 1960s. In the wake of Gardner’s volume, his publisher Clarkson Potter would bring out The Annotated Mother Goose, The Annotated Sherlock Holmes, The Annotated Wizard of Oz, The Annotated Shakespeare, and The Annotated Oscar Wilde. Others established themselves as master annotators: the science fiction writer Isaac Asimov, for instance, produced annotated versions of Don Juan, Paradise Lost, and Gulliver’s Travels in the 1970s and ’80s. Gardner himself went on to annotate Carroll’s The Hunting of the Snark, Coleridge’s Rime of the Ancient Mariner, and G.K. Chesterton’s The Man Who Was Thursday.

The list of books that have been annotated for a popular audience is now in the high dozens. We’ve had annotated editions of Pride and Prejudice, Huckleberry Finn, and The Origin of Species. Several titles—including Uncle Tom’s Cabin, Frankenstein, Little Women, and the stories of Edgar Allan Poe and H.P. Lovecraft—have been annotated more than once. Most of these texts, it should be noted, are in the public domain, a fact that helps explain competing editions like the two annotated versions of The Wind in the Willows published in 2009. According to Weil, Norton will soon offer an Annotated African American Folk Tales, by Henry Louis Gates and Maria Tatar, and an Annotated Classics overseen by Mary Beard.

Though literary works of all kinds have been submitted to the Gardner treatment, children’s classics are by far the most frequently annotated. “I think it needs a component of children’s and adult,” Weil said. “I imagine a parent reading with his or her child.” It’s essential, according to Weil, that these volumes have a “festive” quality; many of them are pegged to anniversaries, like the centennial of Peter Pan and the fiftieth anniversary of The Phantom Tollbooth. In many cases, they sell to adults who loved these books as kids and are interested in revisiting them in greater depth.

Annotation is a form of literary lingering: It allows us to prolong our experience with a favorite book, to hang around the world of a beloved text a bit longer. But it can also serve as a gateway, for younger readers, to the pleasures of scholarship, by pointing to a larger universe of knowledge beyond. I first read The Annotated Alice at the age of eleven, and I was fascinated by its wealth of recondite information. I’m not quite sure why, at that stage of my life, I was interested in the fact that, say, the man in the folded paper hat in one of John Tenniel’s Alice illustrations resembles British Prime Minister Benjamin Disraeli; I’m sure I’d never even heard of Disraeli. And yet I was interested; the book taught me how to be curious about such things. Leafing through Norton’s new anniversary edition, I was surprised at how many of Gardner’s notes I remembered vividly, like his reflection on Carroll’s fondness for the number 42, or Humpty Dumpty’s aristocratic habit of offering his inferiors a single finger to shake. And then there’s this remarkable passage from Gardner’s introduction about nonsense as “a way of looking at existence...akin to religious humility and wonder,” which left a lasting impression on me:

It is part of the philosophic dullness of our time that there are millions of rational monsters walking about on their hind legs, observing the world through pairs of flexible little lenses, periodically supplying themselves with energy by pushing organic substances through holes in their faces, who see nothing fabulous whatever about themselves. Occasionally the noses of these creatures are shaken by momentary paroxysms.

This is still the most terrifying description of sneezing I’ve ever read.

Gardner probably would have liked the idea of Genius. His 1990 sequel, More Annotated Alice, is mostly made up of discoveries and conjectures sent in by readers over the years, each one duly credited for their contribution; as editor Mark Burstein points out in his preface to the new anniversary edition, “Avant la lettre,he was a great believer in crowd-sourcing.” But he might have faulted the execution. Besides “Jabberwocky,” a number of works by Carroll, including the first chapter of Alice’s Adventures in Wonderland, have been annotated by the Genius community—with mixed results. Again there are insights cribbed from Gardner and other established commentators, but also fresh “tates” of varying quality. For the sentence “So she was considering, in her own mind (as well as she could, for the hot day made her feel very sleepy and stupid), whether the pleasure of making a daisy-chain would be worth the trouble of getting up and picking the daisies, when suddenly a White Rabbit with pink eyes ran close by her,” for instance, we get this, added a year ago by an annotator named EwokABDevito:

A daisy-chain is an easy-to-make fashion accessory that consists of a string of daisies tied together by their stems: [Insert picture of little girl with daisy chain in her hair here.] Alice is somewhat ‘bored’ with her existence; even though she is very young and inexperienced, her imagination needs more stimulation to keep her inspired and active.

Whether or not the reader needs “daisy-chain” defined, she certainly doesn’t need this prosaic recapitulation of Alice’s mood, which tells us nothing that Carroll doesn’t already convey. Moreover, EwokABDevito has missed the dramatic point of the sentence completely: This is the introduction of the White Rabbit, a pivotal character in the story whose appearance would seem to deserve some kind of comment.

The usual knock against Genius is that its annotations are incorrect, irrelevant, or offensive, and this is often true. But in some ways the site’s designers may have overcorrected for this problem. In a thoughtful essay on Slate, Katy Waldman notes that Genius, in its brave attempt at “democratizing close reading,” can sometimes play it too safe; the site’s “upvote/downvote system” tends to push “safe, sensible, defensible glosses to the top. These are the Ike Eisenhowers of exegesis, the takes a majority can get behind.” The advantage of having a singular, as opposed to a collective, intelligence in charge of annotating a text is not just that it helps keep things on track; it’s also that it can let things get weird when they need to. “I see no reason why annotators should not use their notes for saying anything they please if they think it will be of interest, or at least amusing,” Gardner declares in his introduction to More Annotated Alice. But even tangents require a judgment call. The problem with many of the Genius annotations of the Alice books isn’t that they’re wildly off base; it’s that they’re dull.

That isn’t a reason to discount Genius’ annotation technology entirely, of course, which may well help to usher in a renaissance of online scholarship. The site has already begun to build exegetical communities around undervalued parts of our culture. A database is only as good as its users, and it’s quite possible that a twenty-first-century Martin Gardner would gravitate toward Genius, or something like it, gradually building up authority and prestige in the community through feats of mental strength. This may be what the site needs to do to be more than a web 2.0 gimmick: Find today’s Gardners, and let them cultivate its soil.