I'll admit that current politics with the threat of eliminating birthright citizenship prompted me to read this title. However, it is all history, albeit fascinating history. Jones does something  more like a people's history, going beyond the landmark moments of the Dred Scott verdict and 13-15th Amendments to the churning of ideas in the period before the decision and amendments. She does this with a focus on Baltimore, MD, though events and decisions in other states are occasionally referenced. 

She divides the concept of citizenship into its component features (including the right to travel between states, to sue, and to bear witness among others), then does a painstaking survey of court cases showing some parts claimed by/awarded to free Blacks even while others are withheld.  She links rights and citizenship and clarifies that free Blacks could have rights in the states and state courts (in some states) while denied them in the country and federal courts. Each feature gets a chapter. Some get interesting stories, others get lists of examples, according to what records exist. Some of the people are mentioned once, others appear off and on through the book. Near the end we learn the fate of those we have come to recognize. 

It enlarges awareness of the time and wealth of actions that contribute to changes that we tend to mark in single moments.