Who is Fender and di Sanza from Jailbird and what is their importance?

Fender and di Sanza are fellow inmates of Finletter Prison where Starbuck is incarcerated for three years. Di Sanza was convicted of fraud, in Starbuck's mind will be convicted again, and is a vocal (and excitable) advocate for the free enterprise/capitalist system. He can be seen as representing the single minded self-righteousness and amorality of those who come to believe fully in the value of that system. Fender was sent there for committing what the government saw as treason but what he (Fender) saw as an act of abject love and devotion (for the details of Fender's story, see Chapter 6). Fender is also a writer, publishing several short stories under a number of different pseudonyms. For further consideration of the thematic implications of this character, see "Themes - Alternative Identities."