Who is Iceberg Slim (aka Robert Beck, aka Macking Youngblood) from Pimp: The Story of My Life and what is their importance?

The main character of the book, Slim recounts his full autobiography. He is a child growing up in the 1920's and 30's as a Black man in a segregated society. Although blessed with the I.Q. of a genius, Slim ends up living as a pimp and going in and out of jail throughout his life. Since this is a time before desegregation, there are few choices for black men in general and even fewer choices for poor black men. Slim has an opportunity to take advantage of his genius when he is sent to Tuskegee University, but he is kicked out due to bad behavior.