Crossing borders: between literature and science – Italian culture of the twentieth and twenty-first centuries has offered significant examples of renewal through crossing boundaries between different disciplines. Several writers (Levi, Calvino, Gadda, Sinisgalli, Del Giudice, Giordano, Arpaia, Odifreddi) have overcome the dichotomy between the two cultures that was denounced by Charles Snow in 1959. Sixty years after the famous essay by Snow, the paper will show several examples of connections between literature and science, by using the concept of the “four frontier customs”: “the transit”, “the trespass”, “the alliance”, and “the conflict”.