Philosophy in the Tragic Age of the Greeks () is an incomplete book by Friedrich Nietzsche. He had a clean copy made from his notes with the intention of publication. The notes were written around 1873. In it he discussed five Greek philosophers from the sixth and fifth centuries BC. They are Thales, Anaximander, Heraclitus, Parmenides, and Anaxagoras. He had, at one time, intended to include Democritus, Empedocles, and Socrates. The book ends abruptly after the discussion of Anaxagoras's cosmogony.