Fictionalized story of the life and times of Sojourner Truth, born Isabella. In this case fictionalized allows the author to tell Sojourner's story in the first person, giving it more vividness and personalization than a biography could ever have. Also it allows Sheehan to imagine what Sojourner was thinking and feeling and to fill in conversations as they might have happened.
I didn't know that much about Sojourner Truth actually, just the basics of her story. The story is compelling and strange. I went and checked a couple parts to see if the novelization was making up parts completely. Everything I checked turned out to be true, including Sojourner (before she had taken that name, or as she says had been given that name by God) getting sucked in to a religious cult. As those things happen, the cult started with what must have been a positive vision of living close to God and sharing God's message, but got more and more toxic over time. The cult leader, Matthias the Prophet, starts getting his ego fed with the adulation and power and gets gradually more debased by it. Not until the cult falls apart in a mess of sex and death and Matthias goes to prison does Sojourner get herself free of it.
So the book is well researched and seems to stick pretty close to the facts. It probably didn't need to be 700 pages long. It is slow in places . It focuses mostly on Isabella's early years. The author says that is deliberate, because that is the part most of us don't know. But it means after 700 sometimes slow pages, the part about the Sojourner we do know and love feels rushed and elided. But still an amazing story of an amazing woman and the terrible ills of the time that she survived and that made her who she was. There are parts that resonate with the racism and hatred this country still struggles with.