Like the novel, the essay is a literary device for saying almost everything about almost anything, usually on a certain topic. By tradition, almost by definition, the essay is a short piece, and it is therefore impossible to give all things full play within the limits of a single essay. But a collection of essays can cover almost as much ground, and cover it almost as thoroughly, as can a long novel. Montaigne's Third Book is the equivalent, very nearly, of a good slice of the Comédie Humaine.
    There are the predominantly personal essayists, who write fragments of reflective autobiography and who look at the world through the keyhole of anecdote and description. There are the predominantly objective essayists who do not speak directly of themselves, but turn their attention outward to some literary or scientific or political theme. … And how splendid, how truly oracular are the utterances of the great generalizers! … The most richly satisfying essays are those which make the best not of one, not of two, but of all the three worlds in which it is possible for the essay to exist.
     Essays belong to a literary species whose extreme variability can be studied most effectively within a three-poled frame of reference. There is the pole of the personal and the autobiographical; there is the pole of the objective, the factual, the concrete-particular; and there is the pole of the abstract-universal. Most essayists are at home and at their best in the neighborhood of only one of the essay's three poles, or at the most only in the neighborhood of two of them.