Who is "The Death of the Last Black Man ..." And Bigger and Bigger from The America Play, and Other Works and what is their importance?

The names of these characters evoke aspects of contemporary African American experience, as opposed to those of the other characters which tend to evoke aspects of the past. "Bigger"evokes the hope and possibility for transcending the centuries-old physical, mental, spiritual, and cultural oppression of slavery. "Voice" evokes how belief systems are defined by what people are told, rather than what they understand or intuit themselves. "Before Columbus" evokes the hope and freedom in black culture and society before the arrival of white people like Columbus.