In Saul Bellow's tragicomic HUMBOLDT'S GIFT (1975), the main character, Charlie Citrine, is a successful writer who is tortured by a feeling of emptiness and by his troubling memories. Through his friend (and sometime mentor), the poet Von Humboldt Fleischer, Citrine learns the importance of the spiritual; and, through the unlikely figure of a gangster named Cantabile, Charlie is reawakened to his responsibilities. The question he grapples with is "how to be a man" in the materialist and antihuman society in which he lives--and then how to find the courage to deal with the answer to that question. The character of Humboldt is heavily based on Delmore Schwartz, who was Bellow's friend. HUMBOLDT'S GIFT was one of Bellow's most successful books, and won the Pulitzer Prize for Fiction.