Kimitachi wa Dou Ikiru ka
Miyazaki derived the film's title from writer Genzaburou Yoshino's 1937 masterpiece of the same name. He added that this book is a story that has great meaning to the protagonist of his film. Yoshino's book centers around a man named Koperu and his uncle, and through Koperu's spiritual growth, it discusses how to live as human beings.
(Source: Anime News Network)