How does Calpurnia fit into the classes of people described (Finches, Cunninghams, Ewells)?

As far as most whites in Maycomb are concerned, Calpurnia is black and belongs to the class of Negros in Maycomb. This would be the lowest class. Calpurnia can also be seen as inhabiting the world of whites because she is such an integral part of the finch household. In many ways she is a mother figure to Scout and Jem. Calpurnia is also educated which sets her apart from most of the black population around Maycomb. She is able to inhabit both worlds without alienating, except for one character, both populations.