In the 1910s, Freud wrote a series of twelve essays, to be collected as Preliminaries to a Metapsychology. Five of these were published independently under the titles: "Instincts and Their Vicissitudes," "Repression," "The Unconscious," "A Metapsychological Supplement to the Theory of Dreams," and "Mourning and Melancholia." The remaining seven remained unpublished, an expression of Freud's ambivalence about his own attempts to articulate the whole of his vision of psychoanalysis. In 1919 he wrote to Lou Andreas-Salome, "Where is my Metapsychology? In the first place it remains unwritten".10 In 1920 he published Beyond the Pleasure Principle, a text with metaphysical ambitions.
central preoccupation at the time of his death – the disentangling of the two theories of psychoanalysis, the metapsychological, or mechanistic, and the psychological, or one of meaning.
metapsychology has generally referred to those parts of psychoanalytic theory that are not immediately referrable to the evidence of conscious behavior but that employ instead mediating concepts such as 'structure, 'drive', 'libido', and so forth.