Yet the value of the two main documents is so inestimable, that if the incompleteness and the shortcomings of the _Poetics_, the unavoidable irrelevance of much of the _Rhetoric_, [Sidenote: _Value of the two main treatises._] were far greater than they are, our gratitude for both would still be hard to exaggerate. We have here not merely the first constituting documents, the earliest charters at once and discussions of European criticism, but we have them from the hand of a master whose very weaknesses make him, as compared with some other masters, specially fit for the office of critic. For the magnificent but almost always _a priori_ and unpractical metaphysics of Plato, for the shrewd but personal and rather unfair polemic of Aristophanes, we have a patient examination of a subject in itself so rich and varied, that one regrets having to point out that its riches and its variety are not quite exhaustive. Nowhere, perhaps, does Aristotle sketch the actual _Wesen_ of the man of letters with the dæmonic completeness of the author of the extraordinary passage attributed to Simylus and quoted formerly; but that might be, and probably is, a mere flash. His own conclusions, only sometimes inadequate, very seldom positively erroneous, exhibit the true modes of criticism as perhaps they have never been exhibited since—with an equal combination of patience and of power. It is impossible for Aristotle to do harm, unless his principles are not merely taken too literally, but augmented and falsified, as was done by the “classical” criticism of the seventeenth and eighteenth centuries. It is impossible for any one who undertakes the office of a critic to omit the study of him without very great harm. Let us first review briefly what seem to be the shortcomings, accidental or essential, of his performance, and then set down what its better parts establish for us as the state of Literary Criticism at the close of the first and greatest age of Greek literature, at the close of the first age of the literature of Europe as a whole.