 In his unpublished manuscripts, Nietzsche sometimes elaborates the topics found in the published works, such as his early 1870s notebooks, where there is important material concerning his theory of knowledge. In the 1880s notebooks—those from which his sister collected together a large selection after his death under the title, The Will to Power: Attempt at a Revaluation of all Values—Nietzsche sometimes adopts a more metaphysical orientation towards the doctrines of Eternal Recurrence and the Will to Power, speculating upon their structure, implications, and intellectual strength as interpretations of reality itself. Side-by-side with these speculations, and complicating efforts towards developing an interpretation which is both comprehensive and coherent, Nietzsche’s 1880s notebooks also repeatedly state that “there are no facts, only interpretations.”