For Mussolini’s 60th birthday, Hitler gave him a de luxe edition of Friedrich Nietzsche’s complete works, bound in blue pigskin. After the war, writers vied to revile the philosopher. Then, in the 1960s, he suddenly became philosophy’s darling. How come? Enter two erotically entangled Italians: Georgio Colli, a philosophy teacher at Lucca from 1942, and