This open access book brings together the texts of the talks presented at the XXIII Amaldi Conference, organized by the Accademia Nazionale dei Lincei (Italy), the U.S. National Academy of Sciences, and the Pugwash Organization, and held in Rome from October 28 to 30, 2024.The main focus was on the risk of potential nuclear conflicts arising from the current international situation, particularly due to the ongoing conflicts in Ukraine and the Middle East. It also analyzed the possible consequences of both local and global nuclear conflicts. Additionally, discussions addressed the role of the scientific community in facilitating the resumption of international dialogue on nuclear disarmament, especially in the East Asian context.Other topics covered included the impact of artificial intelligence and space technology on modern conflicts, as well as prospects for large-scale energy production from nuclear fission and fusion. The chapters are written by experts from various disciplines, representing universities, international organizations, and governments from Europe, the United States, the Middle East, China, and Japan.