I read this for a class I took at my church this summer [we called it Summinary ]. It gives a history of liberal religion and the quest for tolerance for religious freedom. I was amazed at how often, religious change came about due to other power struggles. The Germans were chafing under Roman authority. So when Luther made his religious objections, the powers of state used the theological dispute to their advantage.
A repeated theme was reformers in one decade turning into the old guard against whom the newer thinkers rebelled in the next generation. I was surprised at how enriching I found this read.