Schopenhauer was the pessimist of the 19th century, who discerned by their very human nature, as willing beings, people live's lead invariably to some sort of suffering or another, and that the only salvation from these torments (of disappointment, of jealousy, of lust) was denial of those base impulses. Only through restraint were you free from slavery to the will. His rather famous student Friedrich Nietzsche would later invert this equation. Schopenhauer's prescription for denial also have an aesthetic element, as he argued the struggle to escape the will also provided one with a certain level of detachment and distance from the objects of the world, affording the individual clarity of thought.
    Essentially, if you view reality is an impelling force, which appears to the individual as will, then conflict arises when the individual cannot satisfy those desires, or they prove contradictory. To boil it down then, life is suffering and all people, Schopenhauer said, live in pain. The whole basis of ethics, in fact, rests on sympathy for the pain of others, which he outlined in his essay, On The Suffering Of The World, published after his death in 1851.

    Schopenhauer was born in Danzig, Germany in 1788, into a wealthy & educated family. He traveled widely and was well schooled throughout Europe in this youth, focusing on Immanuel Kant, Plato and the Hindu Upanishads (which he stated later as his greatest influences). However, as his schooling continued, he encountered more and more the influence of Hegel on his studies (en vogue at the time, Hegel's Philosophy of History was a sort of ur-Modern Post-Modern Condition, certainly required reading). Anyway, by 1816, S. begins to make a name for himself, writing a great deal on art, perception, colour, and even collaborating with Goethe. In 1818, though, his masterwork is published, Die Welt als Wille und Vorstellung (The World as Will and Idea, or The World as Will and Representation, depending on the translator), wherein he outlined his philosophy and vision of the world and mind extensively.
    In 1820, he secured a position at University of Berlin, only to be enraged to find few students interested in attending his lectures on account of they're being held the same time as Hegel's across campus. After that, he made it a point to ridicule & revile Hegel (and who can blame him really?) whenever he had the chance, but eventually moved to Frankfurt in 1833 to devote himself exclusively to writing, expanding each of the ideas in his earlier work. He dies of a heart attack on September 21, 1860.

Quotations :
"Every man takes the limits of his own field of vision for the limits of the world." (from Studies in Pessimism, 1851)
"In savage countries they eat one another, in civilized they deceive one another.'' (from Unser Verhalten gegen Andere betreffend', 1851)
"I have long held the opinion that the amount of noise that anyone can bear undisturbed stands in inverse proportion to his mental capacity and therefore be regarded as pretty fair measure of it." (from On Noise)
"There is no more mistaken path to happiness than worldliness, revelry & high life." (Essays, Our Relation to Ourselves, sec. 24)
"The two foes of human happiness are pain and boredom." (Essays, Personality; or What a Man Is)
"All truth passes through three stages: First, it is ridiculed; Second, it is violently opposed; and Third, it is accepted as self-evident." (from On the Wisdom of Life, Aphorism.)
"In the sphere of thought, absurdity and perversity remain the masters of the world, and their dominion is suspended only for brief periods." (from On the Wisdom of Life, Aphorisms.)
"Hatred is an affair of the heart: contempt that of the head." (from The World as Will & Idea, Vol.2, ch.26, sct.324)

1. "Arthur Schopenhauer (1788-1860)," Routledge Encyclopedia of Philosophy (NY: 1998), v.8, p.545-554.
2. Essays of Arthur Schopenhauer, (NY: Burt, n.d.)