There was an old cry, Return to Nature! Let us rather return unto the soul. Nature is great, and her science marvellous; but it is man who knows it. In what he knows it is partial and subsidiary. Know thyself, was the first command of reason; and wisdom was an ancient thing when the sweet influences of the Pleiades and the path of Arcturus with his sons were young in human thought. These late conquests of the mind in the material infinities of the universe, its exploring of stellar space, its exhuming of secular time, its harnessing of invisible forces, this new mortal knowledge, its sudden burst, its brilliancy and amplitude of achievement, thought winnowing the world as with a fan; the vivid spectacle of vast and beneficent changes wrought by this means in human welfare, the sense of the increase of man's power springing from unsuspected and illimitable resources,--all this has made us forgetful of truth that is the oldest heirloom of the race. In the balances of thought the soul of man outweighs the mass that gravitation measures. Man only is of prime interest to men; and man as a spirit, a creature but made in the likeness of something divine. The lapse of aeons touches us as little as the reach of space; even the building of our planet, and man's infancy, have the faint and distant reality of cradle records. Science may reconstruct the inchoate body of animal man, the clay of our mould, and piece together the primitive skeleton of the physical being we now wear; but the mind steadily refuses to recognize a human past without some discipline in the arts, some exercise in rude virtue, and some proverbial lore handed down from sire to son. The tree of knowledge is of equal date with the tree of life; nor were even the tamer of horses, the worker in metals, or the sower, elder than those twin guardians of the soul,--the poet and the priest. Conscience and imagination were the pioneers who made earth habitable for the human spirit; they are still its lawgivers and where they have lodged their treasures, there is wisdom. I desire to renew the long discussion of the nature and method of idealism by engaging in a new defence of poetry, or the imaginative art in any of its kinds, as the means by which this wisdom, which is the soul's knowledge of itself, is stored up for the race in its most manifest, enduring, and vital forms. It is, by literary tradition and association, a proud task. May I not take counsel of Spenser and be bold at the first door? Sidney and Shelley pleaded this cause. Because they spoke, must we be dumb? or shall not a noble example be put to its best use in trying what truth can now do on younger lips? The old hunt is up in the Muses' bower; and I would fain speak for that learning which has to me been light. I use this preface not unwillingly in open loyalty to studies on which my youth was nourished, and the masters I then loved whom the natural thoughts of youth made eloquent; my hope is to continue their finer breath, as they before drank from old fountains; but chiefly I name them as a reminder that the main argument is age-long; it does not harden into accepted dogma; and it is thus ceaselessly tossed because it belongs in that sphere of our warring nature where conflict is perpetual. It goes on in the lives as well as on the lips of men. It is a question how to live as well as how to express life. Each race uses its own tongue, each age its dialect; but, change the language as man may, he ever remains the questioner of his few great thoughts.