Beyond Good and Evil, one of Nietzsche’s four «late period» works, is a philosophical treatise organized into nine parts and 296 short individual sections. In it he explores the concept of morality as taken for granted by contemporary philosophers, and whether «good» and «evil» should be considered just two sides of the same coin.
Philosophers are accustomed to speak of the will as though it were the best-known thing in the world; indeed, Schopenhauer has given us to understand that the will alone is really known to us, absolutely and completely known, without deduction or addition. But it again and again seems to me that in this case Schopenhauer also only did what philosophers are in the habit of doing—he seems to have adopted a popular prejudice and exaggerated it. Willing seems to me to be above all something complicated, something that is a unity only in name—and it is precisely in a name that popular prejudice lurks, which has got the mastery over the inadequate precautions of philosophers in all ages.