For another take on Nietzsche's theory of truth, here's a lecture from Prof. Robert Solomon, one of the stars of The Great Courses series. Solomon describes Nietzsche's concept of truth as perspectivist rather than relativist. (Though, unlike Rick Roderick, Solomon is willing to concede that other Nietzsche interpreters have -- rightly or wrongly -- gone farther.) Solomon's argument sources the origin of Nietzsche's critique to his rejection of the "thing-in-itself," which so consumed Kant and Schopenhauer. Once one is cured of the concept of a "thing-in-itself," then we are all left to determine truth based on upon the world of appearances. But of course, once we are left to determine truth based upon experience -- there is no "God's eye view" by which ultimate truth can be established. In fact, even God could not have a "God's eye view" of the world, in the sense of pure omniscience: there is always context; there is always aspect. Solomon wants to make clear that this is not the same thing as saying that all truths are "relative," if one means by "relative" there are no criteria by which we can judge the relative merits of fact or value statements. But it does mean that truth is complex, not simple, and requires an ability to interpret answers, rather than merely "discovering" them. For more on this subject, perhaps review this thesis submitted by one of Jessica Berry's students.