This is not an essay. Though maybe, in a way, it is. Because it's a strange thing about essays—even talking about them, trying to get at what they are, it's hard not to cleave to the spirit of the essay, that inconclusive, most outwardly formless of forms, which spills and seeps into so many other kinds of writing-memoir, feature, commentary, review—and punctuates every assertion with a qualification, a measure of doubt, an alternate possibility.

So, this might be an essay.

It's this very problem, the want of a strict, inarguable definition of the essay, knowing where it stops and where other forms begin, that has perhaps made the essay one of literature's most misunderstood forms, a "second-class citizen" in the world of letters, according to one of its best-known practitioners, E.B. White. And yet to many who write them, essays are some of literature's most rigorous undertakings—both intellectually taxing and more revelatory than fiction, as they lack the soft membrane of fiction's artifice to buffer the impact of the writer's thoughts on the reader.

Long before postmodernism drew the reader's attention to the naked machinations of literature, there was the essay, laying itself bare, the curtain between the writer and reader already pulled back. The writer, caught in a kind of intellectual flagrante delicto, struggles, tests, sounds things out, finds ideas and discards others. For the reader, the very thrill and energy of the essay comes from this intimate exposure, the art of a writer intensely in dialogue with him or herself, the "dialectic of self-questioning," as essayist Phillip Lopate calls it. O.B. Hardison Jr. sees this self-realization extending even further, to an almost metaphysical level: "The essay is the enactment of the process by which the soul realizes itself even as it is passing from day to day and from moment to moment."

That acting out, that attempt, is the essay's vital center. And so it was coined in the 16th century by Michel de Montaigne, whose own prose works on matters philosophical, literary, and moral seemed to find no place among prescribed forms or genres of writing because of their self-effacing, antiauthoritative posture. He called his effort essai. (The modern translation from the French corresponds simply to "attempt.") And thus was a name given to the form and the process, though it was not necessarily born with Montaigne, as certain rhetorical works dating back to the likes of Seneca and Plutarch can be retrofitted with the designation.

If Montaigne didn't, strictly speaking, invent the form, he certainly gave it its tincture, laying out some of its broad parameters, setting the stage for the later identifiable informalities it would accrue. He rejected systemic thinking and hefty, authoritative rhetoric. He showed readers the colliding intersections of his own thoughts. He didn't begin with conclusions, and often he never found them.

Which is why it's so ironic that for many readers, the introduction to the form begins with a high school homework assignment to write a five-paragraph essay, with its standard introduction, three body paragraphs, and conclusion. Robert Atwan, founding editor of the annual Best American Essays (Houghton Mifflin), points out that this is a perverse inversion of the form. In his foreword to the 1998 edition of the series, which began in 1986, he writes, "It not only paraded relentlessly to its conclusion; it began with its conclusion. Its structure permitted no change of direction, no reconsideration, no wrestling with ideas."

A real essay, Atwan says, never begins with its end.

So what occasions the essay? If a writer has no surefire argument to make, no point to sway the reader toward, why flaunt personal vacillations in print? Why not leave the questions and doubts to the rough draft rather than give them life?

For Richard Rodriguez, the attraction is the essay's public rehearsal of ideas. "I've always thought of the essay as a way of responding to public life," he says. "For me, the drama of the essay is the way the public life intersects with my personal and private life. It's in that intersection that I find the energy of the essay."

Scott Russell Sanders employs the form for self-revelation. "I write essays as a way of making discoveries about my own life, about the world, about my past," he says. "The essay is a seeking of a pattern, meaning, or understanding in an area where I'm bewildered, puzzled, or confused."

Both writers have worked extensively in other forms. And they keep finding themselves returning to the essay for the allowances it makes for them.

Another compelling feature of the essay is that it opens wide the doors of structural possibility. Essays inherently lend themselves to meandering, anecdote, and disclosure. "They're amorphous; they're protean," says Cynthia Ozick. "They have a million forms, and that's part of the wonder and the freedom of the essay."

And therein also lies the essay's struggle for identity, the point at which it threatens to dissolve into so many other things or into nothing at all. Any form, after all, must have shape, no matter how pale its lines or fluid its borders.

Lopate, editor of The Art of the Personal Essay (Anchor Books, 1994), believes that the true essay is never formless. "It follows a track of someone's thoughts," he says. "So it may not have the same form as a short story, and it may not release its epiphanies in the same way as short fiction, but it generally has a rise and fall, and it appears to dig up something, to reach deeper understandings than it began with, and all that's a kind of form."

Atwan sees the essay as having a kind of "intellectual plot." He says, "There's something going on, some dilemma, something at issue."

And the essay is not averse to employing the devices of other forms, says Ozick, who has published novels, short stories, criticism, and essays. "The nonfiction form can give you some of the enchantments of the fiction form, including revelations, moments of suspense, moments of climax, moments of crescendo," she says.

The prolific Joyce Carol Oates, editor of The Best American Essays of the Century (Houghton Mifflin, 2000), agrees that many contemporary essayists are verging on fiction's domain. "The essayist may be embroidering a little, using some of the devices of the fiction writer," she says. "There's a heightening of suspense, a recollection of dialogue and detail."

This, she says, breaks from 19th-century excursions into the form, most notably in the works of Ralph Waldo Emerson and Henry David Thoreau. "The older form is much more rhetorical," Oates says, "and the newer form is much more cinematic."

Yet whatever it might borrow from fiction—or film, for that matter—Lopate says, the essay reverses one fundamental rule of good fiction writing: Show, don't tell. When writing an essay, Lopate says, "It's not enough to render the experience. You also have to put it in perspective. It's not enough to show. You also have to tell."

And regardless of the structural decisions the essayist arrives at, there is another caution: The essay cannot simply become an exercise in narcissism. "It's not fundamentally about the essayist," says Sanders. "The essay speaks about how the mind and the heart of the essayist intersect with something much larger than the essayist."

Rodriguez agrees. "For me, there's a rigor to the essay," he says. "I require that the essay I write in some sense be about experiences or ideas that other people are proposing or arguing about. It cannot simply be about my experience."

Still, the essay's beating heart is the writer him- or herself, the story (or stories) subordinate to what the individual is making of it (or them). "I find that the reliance the reader puts upon an essay is a reliance that I seem to bear rather directly," says Pulitzer Prize–winning novelist Richard Ford. "They want an inquiring intelligence seen to be at work, leading to some distillation or expression of intelligence derived from real-life experience."

But ironically, this desire for intelligence and insight from the essay, with its critical and analytical tendencies, may have put it in lower standing than other literary forms. "In the early twentieth century, the essay was used to explain works of modernism, and it became a great critical tool," Atwan says. "It was used to explain poetry, drama, and fiction, and as a result of that it wasn't considered a literary form itself."

By the 1960s, he says, it had become a kind of endangered literary species, relegated to the lesser tier of journalism and commentary. Putting the essay in critical service to other forms had diminished its own standing, making for a largely absent body of critical theory and vocabulary on the form itself.

And then, a strange twist. As the essay dwindled away in print, exiled to a few literary publications, it began to emerge from unexpected sources. National Public Radio began broadcasting essays on its daily news programs, a practice that can be seen as having led to present-day weekly shows like Public Radio International's This American Life. Television introduced its own forays, from Andy Rooney's pieces on CBS's 60 Minutes to essays by Rodriguez on PBS's The NewsHour With Jim Lehrer. Essays began to abound on the Internet in online magazines like Slate and Salon, introducing hypertextuality to the form and vastly broadening its readership.

This revitalization was coupled in the 1990s with the public's growing interest in memoir, the essay's closest literary cousin. Readers' hunger for self-disclosure became nearly insatiable, and readers made genuine stars out of writers like David Sedaris, a humorist-essayist who first gained popularity on NPR, went on to publish collections of his personal musings, and now routinely sells out large theaters for his readings, evoking a widespread popularity of the form not seen since the days of Mark Twain. Suddenly, it was not inconceivable for the essayist to become a rock star.

Rodriguez says his own work, as presented in his appearances on television, introduced a counterpoint to the news that has struck a chord with viewers. "There was some desire to end the official discussion of the day's news with a human voice that was simply mulling it over," he says. "It was a reminder that all this news will play against a consciousness."

But what radio, television, and the Internet lent the form in popularity, even poignancy, they threatened in the essay's potency. Ford, who has written numerous essays for radio, says the medium's limitations are considerable. "The thoroughness that the mind is capable of is foreshortened," he says. "References and second thoughts are foreshortened. Pithiness is rewarded about a subject for which pithiness is not usually a virtue."

Sanders says the Internet's hypertextual nature, too, can have an adverse effect on essay writing. "It will tempt writers to write in more fractured, more fragmented ways, because that's the way most information comes to us now," he says.

Oates agrees. "The qualities that we see on the Internet are brevity and succinctness, and maybe a little bit of flippancy and shallowness," she says. "So you don't quite come away with as much depth on the Internet."

Still, however mutable other media may have made it, the essay has heartily rebounded from the endangered-species list. Anthologies, including the Best American Essays series, are flourishing, and essays continue to find a regular home in periodicals ranging from The New Yorker and Harper's to Boulevard, the Yale Review, the Gettysburg Review, and the Georgia Review.

But if the essay has found itself on more solid footing than it was 50 years ago, if the word itself enjoys greater literary standing ("The term no longer has the negative resonance that it did when I started the series," Atwan says), there is still the matter of its shimmering, protoplasmic borders. When does the mere "essayistic" begin to walk securely on the terra firma of the essay? Where does the essay begin to strain under the devices of other forms—the lengthy, unmediated divulgence of the memoir, the multiple points of authority of journalism, the evaluative checklist of the review? When will it offer us the structural assurances of the poem, the short story, the novel?

Perhaps it is the essay's very nature to deny us such certainty. For there just might not be an actual territory of the essay, but only the trying to find it.

Michael Depp is the Reuters correspondent for Louisiana. He contributes to numerous periodicals and to The Dictionary of Literary Biography (Gale). He lives in New Orleans.