It is risky to think that solitude constitutes the black thread that leads to a full understanding of Nietzsche's philosophy, explaining it from a position that necessarily involves the person of Nietzsche and links it to each of his ideas as the fruit of his own life, rather than as philosophical dissertations on a world that is foreign to him and to which he does not wish to belong; such a black thread cannot exist, at least not in a philosopher who makes contradiction the very essence of his work. Nevertheless, solitude is Nietzsche's most faithful companion, the only one who is with him from the first years of his life until the moments before his death; he carries it among his flesh, suffers it, lives it, rejects it when it seems uncontrollable, and seeks it again when he needs it to write; For it is not only the physical loneliness that was always latent, but a spiritual and ideological loneliness, a feeling of being alone and knowing oneself to be alone, struggling to liveunder the sensation of not belonging to anything or anyone, of being untimely and at the same time ahead of the historical moment in which he lived.