Friedrich Wilhelm Nietzsche (October 15, 1844 – August 25, 1900) was a 19th-century German philosopher, poet, composer and classical philologist. He wrote critical texts on religion, morality, contemporary culture, philosophy and science, displaying a fondness for metaphor, irony and aphorism.

Nietzsche's influence remains substantial within and beyond philosophy, notably in existentialism, nihilism and postmodernism. His style and radical questioning of the value and objectivity of truth have resulted in much commentary and interpretation, mostly in the continental tradition. His key ideas include the death of God, perspectivism, the Übermensch, the eternal recurrence, and the will to power. Central to his philosophy is the idea of "life-affirmation", which involves an honest questioning of all doctrines that drain life's expansive energies, however socially prevalent those views might be.