Emerson wrote numerous essays on nature, beauty, spirit, and how all three are related. Nature and Self-Reliance are probably his two best-known works and are often read in high school American Lit. courses as well as your basic American Humanities college course. He's probably one of the most quoted authors you'll come across when it comes to magnets and inspirational calendars. Here's a taste of his more savoury stuff:
We are not built like a ship to be tossed, but like a house to stand.
The true philosopher and the true poet are one, and a beauty, which is truth, and a truth, which is beauty, is the aim of both.
A more secret, sweet, and overpowering beauty appears when a man's heart and mind open to the sentiment of virtue...He learns that his being is without bound.
I do not wish to treat friendships daintily, but with roughest courage. When they are real, they are not glass threads or frostwork, but the solidest thing we know.
Idealism sees the world in God. It beholds the whole circle of persons and things, of actions and events, of country and religion, not as painfully accumulated, atom after atom, act after act, in an aged creeping Past, but as one vast picture, which God paints on the instant eternity, for the contemplation of the soul.