Friedrich Nietzsche (1844–1900) developed his philosophy during the late 19th century. He owed the awakening of his philosophical interest to reading Arthur Schopenhauer's Die Welt als Wille und Vorstellung (The World as Will and Representation, 1819, revised 1844) and said that Schopenhauer was one of the few thinkers that he respected, dedicating to him his essay Schopenhauer als Erzieher (Schopenhauer as Educator), published in 1874 as one of his Untimely Meditations.
Since the dawn of the 20th century, the philosophy of Nietzsche has had great intellectual and political influence around the world. Nietzsche applied himself to such topics as morality, religion, epistemology, poetry, ontology, and social criticism. Because of Nietzsche's evocative style and his often outrageous claims, his philosophy generates passionate reactions running from love to disgust. Nietzsche noted in his autobiographical Ecce Homo that his philosophy developed and evolved over time, so interpreters have found it difficult to relate concepts central to one work to those central to another, for example, the thought of the eternal recurrence features heavily in Also sprach Zarathustra (Thus Spoke Zarathustra), but is almost entirely absent from his next book, Beyond Good and Evil. Added to this challenge is the fact that Nietzsche did not seem concerned to develop his thought into a system, even going so far as to disparage the attempt in Beyond Good and Evil.
