The completed works from Beyond Good and Evil to Ecce Homo stand in the foreground of the creative period of Nietzsche's life the background of which is the mass of unfinished material best referred to collectively as the Revaluation. This material has played a part in Nietzsche studies out of proportion to its importance; indeed, discussion of his later philosophy has been haunted by the shadow-existence of the Revaluation, and the practice of quoting from it side by side with the finished works as if both possessed equal validity as 'Nietzsche's opinions’ has blurred the distinction between what he himself published, or prepared for publication, and what he rejected for publication. Three considerations are involved: Nietzsche's own attitude towards the Revaluation; the question of its publication; and the quality of the material itself.

By the end of 1888 Nietzsche had been fighting against ill-health for sixteen years. It is no romantic exaggeration but the simple truth to say that what kept him alive during the latter half of this period was his sense of mission; and the more desperately ill he was, the more desperately did he magnify the significance of that mission. In the sense in which he used the expression, Nietzsche's mission was a delusion. Its vehicle was the grandiose project called at first The Will to Power, planned as a work to which Zarathustra would stand as an introductory poem. Its scope was to be very large: a thoroughly detailed account of his philosophy. He began assembling material for it during 1884, and the Nachlass contains very many plans for its layout: the one dated the 17th March 1887 was arbitrarily selected by Elizabeth as the framework for her compilation called The Will to Power.

The first mention of the projected book in Nietzsche's published writings occurs in the Genealogy, where he directs the reader in a parenthesis ‘to a work I have in preparation: The Will to Power.