That's actually her name.
She adopted the name in 1953 and then walked across the United States for 28 years advocating against war, and for peace. Her birth name was Mildred Lisette Norman but during her pilgrimage no one ever knew her by her birth name. They called her 'Peace' because that was her legal name.
During my North-South trek from NYC to Miami, one of my couchsurfing hosts who lived in Elkton, Maryland specifically put this book on the end table next to the couch that I would be sleeping on.
He didn't tell me about it.
I didn't see it the first day that I was there but it came into sight on the second day. It actually was laying there in a very obvious place but I guess I was too fatigued to notice, but when I did see it, time stood still.