 Thus Spoke Zarathustra, A Book for All and None (Also Sprach Zarathustra, Ein Buch für Alle und Keinen, 1883–85), is one of Nietzsche’s most famous works, and Nietzsche regarded it as among his most significant. It is a manifesto of personal self-overcoming, and a guidebook for others towards the same revitalizing end. Thirty years after its initial publication, 150,000 copies of the work were printed by the German government and issued during WWI as inspirational reading to the young soldiers, along with the Bible. Though Thus Spoke Zarathustra is antagonistic to the Judeo-Christian world-view, its poetic and prophetic style relies upon many, often inverted, Old and New Testament allusions. Nietzsche also filled the work with nature metaphors, almost in the spirit of pre-Socratic naturalist philosophy, which invoke animals, earth, air, fire, water, celestial bodies, plants, all in the service of describing the spiritual development of Zarathustra, a solitary, reflective, exceedingly strong-willed, sage-like, laughing and dancing voice of heroic self-mastery who, accompanied by a proud, sharp-eyed eagle and a wise snake, envisions a mode of psychologically healthier being beyond the common human condition. Nietzsche refers to this higher mode of being as “superhuman” (übermenschlich), and associates the doctrine of eternal recurrence—a doctrine for only the healthiest who can love life in its entirety—with this spiritual standpoint, in relation to which all-too-often downhearted, all-too-commonly-human attitudes stand as a mere bridge to be crossed and overcome.