Thus Spoke Zarathustra is perhaps Nietzsche's most enduringly well-read work with non-academics. In it, Nietzsche chooses to express his ideas through the voice of the ancient Persian prophet Zarathustra (aka Zoroaster). Zarathustra says, "'We have invented happiness,' say the last men, and they blink." The people cheer, and ask Zarathustra to turn them into these last men. Just then, a tightrope walker begins walking between two towers in the town. The main theme of the text, expressed in Zarathustra's first address to the people after coming down from his mountain cave, is the transformation or further evolution of humankind. The story unfolding in the text involves also Zarathustra's own struggle and transformation.