Shortly before his mental breakdown at the beginning of January 1889, Friedrich Nietzsche wrote in Ecce Homo (1888) that “out of my writings there speaks a psychologist who has not his equal, that is perhaps the first thing a good reader will notice.” Since then, posterity has subscribed to his verdict. Today his opus is regarded as an essential contribution to a psychology of the unconscious and he himself is supposed to have been a precursor to psychoanalysis. This is rather surprising, as Nietzsche's philosophy contains no explicit theory of the unconscious; in other words, the concept of the unconscious is not at the center of his thinking. Instead one can – especially in the early writings – detect an understanding of the unconscious which aligns Nietzsche with a tradition of thought from early Romanticism to Schopenhauer, a concept with which he assumed his learned audience would be familiar. But at the same time he began – in his unpublished observations, and under the influence of contemporary scientific and linguistic theories – to bestow his own meaning upon this conception of the unconscious. This stream of thought led, in connection with his theory of the drives, to a somatic understanding of the unconscious in his middle period. As I will argue, Nietzsche's middle-period writings already pointed towards the dissolution of the concept of the unconscious, a process that was finally completed in Nietzsche's late writings on the will to power.