I think this book is absolutely worth reading, but I can’t rate it based on what it is. 

The author presents an amazingly well researched book on the lives of biracial enslaved people in America. The issue is this book is published as a biography of Mary Lumpkin. While she is definitely emphasized and what we know of her life is thoroughly discussed, by the authors own admission as an enslaved woman, there is little to no documentation of her own words and little confirmed documentation of her life outside of confirmed information about her living in the prison, having children with the prison owner, and her demands that her children be free and what is documented of her husbands business and legal activities. 

However there is a TON of information about many enslaved biracial individuals, general history of multiple states fighting for or against slavery, important organizations and schools and lives of enslaved people who were better documented. I absolutely think this book is worth reading, but the information on Mary Lumpkin (outside of inferences about what she may have done in various situations) could fill about a chapter and a half of the book itself. If this was marketed as a book about biracial individuals and the history of slavery, it would easily be a 5 star read for me.