I do not ask it for sordid reasons. What makes a novel sell 100,000 copies, or a short story bring $1000? may seem the same query; but it does not get the same answer, or, apparently, any answer valuable for criticism. A cloud descends upon the eyes of those who try to teach how to make money out of literature and blinds them. Their books go wrong from the start, and most of them are nearly worthless. They propose to teach the sources of popularity, yet instead of dealing with those fundamental qualities of emotion and idea which (as I hope to show) make popularity, their tale is all of emphasis, suspense, beginnings and endings, the relativity of characters, dialogue, setting-- useful points for the artisan but not the secret of popularity, nor, it may be added, of greatness in literature. Technique is well enough, in fact some technique is indispensable for a book that is to be popular, but it is the workaday factor in literature, of itself it accomplishes nothing. But technique can be taught. That is the explanation of the hundred books upon it, and their justification. You cannot teach observation, or sympathy, or the background of knowledge which makes possible the interpretation and selection of experience--not at least in a lesson a week for nine months. Hence literary advisers who must teach something and teach it quickly are drawn, sometimes against their better judgment, to write books on technique by which criticism profits little. Technical perfection becomes their equivalent for excellence and for popularity. It is not an equivalent. More than a mason is required for the making of a statue. I disclaim any attempt to teach how to be popular in this essay, although deductions may be made. I am interested in popularity as a problem for criticism. I am interested in appraising the pleasure to be got from such popular novels as "The Age of Innocence," "Miss Lulu Bett," "If Winter Comes," or "The Turmoil" --and the not infrequent disappointments from others equally popular. I am especially interested in the attempt to estimate real excellence, an attempt which requires that the momentarily popular shall be separated from the permanently good; which requires that a distinction be made between what must have some excellence because so many people like it, and what is good in a book whether many people like it or not. Such discrimination may not help the young novelist to make money, but it can refine judgment and deepen appreciation.