Mumbet's Declaration of Independence by Gretchen Woelfe, illustrated by Alix Delinois (Carolrhoda Books, 2014)
Based on a true story, this book is about Elizabeth "Mumbet" Freeman. She was a slave in 18th century Massachusetts who, with the help of a lawyer, fought for her rights based on the Massachusetts Constitution assertion that "All men are born free and equal, and have certain natural, essential, and unalienable rights." Amazingly, she won, and gained her freedom. The court decision led to Massachusetts declaring slavery unconstitutional in 1783.
It's a shame that her story isn't written about in history textbooks (that I've seen). I became familiar with Mumbet when my mom was researching our family history. My several-times great-grandfather Pieter Hogeboom bought Mumbet and another slave named Lizzy (portrayed in this book as her daughter, although it's not known for sure) and later gave her to his daughter Hannah when she married Colonel John Ashley. Hannah was cruel to her slaves, a famous scene portrayed below, showing her about to strike Lizzy with a hot coal shovel, before Mumbet steps in to protect her. Not a great claim to fame for me, but Hannah Ashley's not a direct ancestor, so it's not quite as bad, I guess?
If you'd like to learn more about Mumbet, there is also a great video from the PBS show Finding Your Roots with Henry Louis Gates, Jr. where he investigates Kyra Sedgwick's ancestry, which includes the lawyer Theodore Sedgwich who helped Mumbet gain her freedom and who she later lived with and worked for. You can view that here.