“The essay, as a literary form, is pretty well extinct,” Philip Larkin wrote gloomily in 1984. Extinct was the right word, capturing the sense of an organism that could no longer survive in a changed environment. “It belonged to an age when reading—reading almost anything—was the principal entertainment of the educated class,” Larkin argued, an appetite that “called for a plethora of dailies, weeklies, monthlies and quarterlies, all having to be filled.” Now it is television and the movies that cry out for ever more “content,” while the lush Victorian ecosystem has thinned out to half-a-dozen serious magazines, most of which have only slightly more appetite for essays than for that other obsolete form, the short story.

It is strange, then, to look around a quarter-century after Larkin and discover that we are living in a golden age of essays, or of ruminative writings that call themselves essays. Books of essays regularly turn up on the best-seller lists; many of their authors are stars on the radio, especially on the cult program “This American Life.” In the HBO show “Girls,” the character portrayed by Lena Dunham declared her ambition to become a writer and “the voice of my generation,” but she did not hope to write the Great American Novel: she wanted to produce a book of essays. Here as in so many of its details, “Girls” proves to be a faithful stenographer of its moment. A talented writer such as John Jeremiah Sullivan might, fifty years ago, have tried to explore his complicated feelings about the South, and about race and class in America, by writing fiction, following in the footsteps of Walker Percy and Eudora Welty. Instead he produced a book of essays, called Pulphead, on the same themes; and the book was received with the kind of serious attention and critical acclaim that were once reserved for novels.

The resurrection of the essay is in large measure a mirage.

But all is not as it seems. You do not have to read very far in the work of the new essayists to realize that the resurrection of the essay is in large measure a mirage. For while the work of writers such as David Sedaris, Sloane Crosley, John Jeremiah Sullivan, and Davy Rothbart are described as essays—My Heart Is an Idiot: Essays, is the title of Rothbart’s new book—they have little in common with what was once meant by that term. The new essay, like the old essay, is a prose composition of medium length; but beyond that the differences are more salient than the resemblances. Larkin was not all wrong.

The essay, traditionally, was defined by its freedom and its empiricism—qualities that it inherited from its modern inventor, Montaigne. “What do I know?” Montaigne asked, and the essay is the form that allows both the “I” and the thing it knows equal prominence. For this reason, the essay could address any subject, exalted or trivial, as long as it displayed the mind of the writer engaged with the world. The subjects in The Oxford Book of Essays, edited by the late John Gross, range from truth and dreams to wasps and the Hoover Dam. Not coincidentally, some of the greatest essays, from Addison on Paradise Lost to Mill on Coleridge, are engaged with texts, which is to say, with other minds. For the essay is one of the purest ways for a writer’s mind to record its own motions, which are the basis of prose style.

The self, then, has always been at the heart of the literary essay. But the new essay is exclusively about the self, with the world serving only as a foil and an accessory, as a mere staging ground for the projection of the self. Formally, one might describe the work of Sedaris, Crosley, Rothbart, and company as autobiographical comic narrative: short, chatty, funny stories about things that happened to me—weird things, or ordinary things that are made weird in the telling. What we now call an essayist used to be called a humorist. Sedaris’s books are sold as essays, but he is plainly trying to be Thurber, not Addison.