Here on a shelf are a Dictionary, a History of America, a text on Chemistry, which we read or study for information; on a higher shelf are _As You Like It_, _Hiawatha_, _Lorna Doone_, _The Oregon Trail_, and other works to which we go for pleasure when the day's work is done. In one sense all these and all other books are literature; for the root meaning of the word is "letters," and a letter means a character inscribed or rubbed upon a prepared surface. A series of letters intelligently arranged forms a book, and for the root meaning of "book" you must go to a tree; because the Latin word for book, _liber_, means the inner layer of bark that covers a tree bole, and "book" or "boc" is the old English name for the beech, on whose silvery surface our ancestors carved their first runic letters. So also when we turn the "leaves" of a book, our mind goes back over a long trail: through rattling printing-shop, and peaceful monk's cell, and gloomy cave with walls covered with picture writing, till the trail ends beside a shadowy forest, where primitive man takes a smooth leaf and inscribes his thought upon it by means of a pointed stick. A tree is the Adam of all books, and everything that the hand of man has written upon the tree or its products or its substitutes is literature. But that is too broad a definition; we must limit it by excluding what does not here concern us. [Sidenote: BOOKS OF KNOWLEDGE AND OF POWER] Our first exclusion is of that immense class of writings--books of science, history, philosophy, and the rest--to which we go for information. These aim to preserve or to systematize the discoveries of men; they appeal chiefly to the intellect and they are known as the literature of knowledge. There remains another large class of writings, sometimes called the literature of power, consisting of poems, plays, essays, stories of every kind, to which we go treasure-hunting for happiness or counsel, for noble thoughts or fine feelings, for rest of body or exercise of spirit,--for almost everything, in fine, except information. As Chaucer said, long ago, such writings are: For pleasaunce high, and for noon other end. They aim to give us pleasure; they appeal chiefly to our imagination and our emotions; they awaken in us a feeling of sympathy or admiration for whatever is beautiful in nature or society or the soul of man. [Sidenote: THE ART OF LITERATURE]