Final answer:
Douglass addresses his book to a wide audience and aims to educate people about slavery and the importance of literacy.
Step-by-step explanation:
Fredrick Douglass addresses his book to a wide audience, including both those who support and those who oppose slavery. He aims to educate people about the atrocities of slavery and the importance of literacy in order to bring about social change. The intended audience affects his argument by allowing him to expose the brutal reality of slavery and challenge the prevailing beliefs and justifications of the time.