Although scholars usually take it for granted that a philosopher's later thinking supersedes his earlier thinking, this periodizing proves complicated in Nietzsche's case. For he himself privileges above all his other works Thus Spoke Zarathustra, a book he wrote before his widely acknowledged twin masterpieces Beyond Good and Evil and On the Genealogy of Morals. According to Nietzsche, these later works are “fish hooks” (Angelhaken) meant to attract and prepare readers for the superior insights of Zarathustra. These later works, he tells us, are No-saying, destructive books focused on the contemporaneous; while Zarathustra is a Yes-saying, constructive book focused on the future (EH BGE). Contrary to scholarly expectation, then, Nietzsche instructs us to think of the analyses in his later books as preemptively superseded by the philosophy of Zarathustra.

Most Nietzsche scholars today ignore this instruction. Although they sometimes cite Zarathustra as a source of confirming textual support, they mostly regard this work as an embarrassment that needs to be finessed. Their chief reasons for this opinion are well known. First, Zarathustra is a poetic fictional work that is not written in Nietzsche's own voice. And, second, it centers around two idiosyncratic philosophical ideas – the superhuman and eternal recurrence – which are not substantially revisited in any of his later works. As for Nietzsche's instruction mentioned above, scholars contend that it cannot be taken seriously because it appears for the first and only time in Ecce Homo, the book he was writing as he quickly approached his breakdown.