We sometimes hear that essays are an old-fashioned form, that so-and-so is the 'last essayist', but the facts of the marketplace argue quite otherwise. Essays of nearly any kind are so much easier than short stories for a writer to sell, so many more see print, it's strange that though two fine anthologies (collections) remain that publish the year's best stories, no comparable collection exists for essays. Such changes in the reading public's taste aren't always to the good, needless to say. The art of telling stories predated even cave painting, surely; and if we ever find ourselves living in caves again, it (with painting and drumming) will be the only art left, after movies, novels, photography, essays, biography, and all the rest have gone down the drain--the art to build from. Essays, however, hang somewhere on a line between two sturdy poles: this is what I think, and this is what I am. Autobiographies which aren't novels are generally extended essays, indeed. A personal essay is like the human voice talking, its order being the mind's natural flow, instead of a systematized outline of ideas. Though more changeable or informal than an article or treatise, somewhere it contains a point which is its real center, even if the point couldn't be uttered in fewer words than the essayist has used. Essays don't usually boil down to a summary, as articles do, and the style. of the writer has a 'nap' to it, a combination of personality and originality and energetic loose ends that stand up like the nap (绒毛) on a piece of wool and can't be brushed flat. Essays belong to the animal kingdom, with a surface that generates sparks, like a coat of fur, compared with the flat, conventional cotton of the magazine article writer, who works in the vegetable kingdom, instead. But, essays, on the other hand, may have fewer 'levels' than fiction, because we are not supposed to argue much about their meaning. In the old distinction between teaching and storytelling, the essayist, however cleverly he tries to conceal his intentions, is a bit of a teacher or reformer, and an essay is intended to convey the same point to each of us. An essayist doesn't have to tell the whole truth and nothing but the truth, he can shape or shave his memories, as long as the purpose is served of explaining a truthful point. A personal essay frequently is not autobiographical at all, but what it does keep in common with autobiography is that, through its tone and tumbling progression, it conveys the quality of the author's mind. Nothing gets in the way. Because essays are directly concerned with the mind and the mind's peculiarity, the very freedom the mind possesses is conferred on this branch of literature that does honor to it, and the fascination of the mind is the fascination of the essay. According to the passage the changes in readers' taste ______.