What kinds of knowledge about themselves does he are kept from slaves, & why does he believe this is important?

Douglass begins his autobiography in a traditional fashion, giving his parentage and information about his birthplace and early formative events. However, his birth and childhood differed demonstrably from those of most Americans – he was a slave. He lamented the fact that he did not know his birthday and thus his own age, and that he had no idea who his father was, despite a few suspicions. Douglas says information about identity was withheld on purpose to rob slaves of purpose and self determination, "..and it is the wish of most masters within my knowledge to keep their slaves thus ignorant."