Ugo Spirito's Memoirs of the Twentieth Century is the intellectual autobiography of one of the most original and anticonformist contemporary Italian philosophers. In it, Spirito makes an evaluation of his long career (spanning from the decade of the 20's to that of the 70's of the twentieth century) as a thinker who was never satisfied with any theoretical or philosophical system, while constantly aiming at finding a definitive truth: the "incontrovertible" or absolute. The various stages of his search deal with different philosophical and scientific systems - from positivism to actual idealism, from problematicism to omnicentrism, from scientism to neoproblematicism - revealing at the same time an inherent antinomic procedure that does not permit him to take any truth for granted. At the end of his life, Spirito realized that he could only be sure of his present state of "unawareness," thus challenging the validity of his lifelong investigative activity. "Man cannot know himself," Spirito wrote. Confronted with the manifestations of life and universe, he could not help but feel a sense of "surprise and astonishment." Throughout his life, he was only a spectator of his destiny, not the conscious creator of it, as he believed in the early stage of his career. Consequently, he reached a position of negating any value system, bordering on skepticism and nihilism. Within this context, he offered a post-modern interpretation of life. This interpretation was also Spirito's conclusion, and as such, implied a rethinking about other faiths, both political and ideological, that for more than fifty years would develop parallel to philosophical faith. Consequently, he revisited some of the most important philosophical and political personalities who interpreted or materialized those faiths, from Benedetto Croce to Gentile, from Benito Mussolini to Giovanni Bottai, from Togliatti to Pope Paul VI. Spirito was not a thinker who remained secluded within the ivory tower of pure investigation, but in an effort to modify society according to principle of the identification of philosophy with life, he tried to act upon it by following thoughts with action. Memoirs of the Twentieth Century is divided in two parts: one purely autobiographical and theoretical, and the other more historical, where Spirito narrates his relationship with the above-mentioned personalities, as a way of testing the validity of his beliefs. Indeed, one can perceive his moment of adherence to each of the different approaches expounded, only to subsequently detach himself from them. For the English-speaking reader, the second part will appear more interesting and poignant, since Spirito's involvement with history foretells the intellectual fate of a nation. Memoirs of the Twentieth Century is a reflection on life, in which personal history serves as a vehicle for judgment upon an entire century.