Perhaps no other modern philosopher has had so wide an influence as F.W. Nietzsche (1844-1900). A brilliant student and classical scholar, appointed to a professorship at Basel when he was 24, he enjoyed the friendship of such diverse people as Burckhardt the historian and Wagner the composer. Although living most of his life in physical pain and social isolation, he nevertheless continued fearlessly to explore philosophical problems and make important contributions to German prose until his collapse into insanity in 1889.
Among the philosophers influenced by his work were Sartre, Jaspers, Heidegger, and Foucault; among the novelists were Hesse, Mann, and Kazantzakis;among the psychologists Jung and Freud; among composers, Delius, Richard Strauss, and Gustave Mahler.

Nietzsche's major works are:
The Birth of Tragedy
Human All too Human
The Dawn
The Gay Science
Thus Spoke Zarathustra
Beyond Good and Evil
The Genealogy of Morals
Twilight of the Idols
The Antichrist
Ecce Homo
The Will to Power (nachlass)

In the 1960s, Nietzsche's introduction to American readers was facilitated by the translations and writings of Walter Kaufmann, bringing his philosophy to a new generation of English readers.

Online resources:

Friedrich Nietzsche (Stanford Encyclopedia of Philosophy)

The Nietzsche Channel (German, English translations)

Nietzsche Source - Home

(attempting to provide a complete edition in German of all of Nietzsche's writings, as well as a digital reproduction of all of N's estate)