Nietzsche's treatises outline his thoughts "on the origin of our moral prejudices", thoughts a long time in the making and previously given brief expression in his Human, All Too Human (1878). Nietzsche attributes the desire to publish his "hypotheses" on the origins of morality to reading his friend Paul Rée's book The Origin of the Moral Sensations (1877) and finding the "genealogical hypotheses" offered there unsatisfactory.
Nietzsche has come to believe that "a critique of moral values" is in order, that "the value of these values themselves must be called into question". To this end he finds it necessary to provide an actual history of morality, rather than a hypothetical account in the style of Rée, whom Nietzsche refers to as an "English psychologist" (using the word "English" to designate a certain intellectual temperament rather than a nationality).