For fifteen years between 1817 and 1832 Giacomo Leopardi's notebook the Zibaldone grew like an expanding universe, recording the emergence and development of his thought until, on 4 December 1832, on page 4526, it fell silent. Philosophical reflections, private memories, poetry, observations on politics and society are only some of the creative expressions of Leopardi's quest, which both enriched his everyday life and at the same time sheltered him from the tyranny of rationality and the death of illusions which he perceived as intrinsic to modernity. There is no other work in world literature quite like it, and yet, strictly speaking, the Zibaldone is not even a work. Private in character but constantly opening up to virtual interlocutors, it gained readers only on publication sixty years after Leopardi's death. Its importance in Western thought, however, is yet to be fully appreciated, not only in terms of its content but also in terms of its form. In this major new study, Cori follows Leopardi's philosophical journey and traces the origin of a sensibility towards the ephemeral, the hyper-real and the simulacrum, which would only truly be understood during modernity and post-modernity, and which Leopardi is the first Italian thinker to perceive.