The Protestant Ethic and the Spirit of Capitalism (book)
The Protestant Ethic and the Spirit of Capitalism by Max Weber should be read after Concerning Christian Liberty by Martin Luther. Luther founded Protestantism by removing "works" from Christianity and saying that all that matters is faith. This seems to throw out consideration for moral action. But as Protestantism developed, one sees a clear emphasis on moral action and "The Protestant Ethic" explains how this happened. The later Protestant movements explain that works are proof of faith and that no one with faith could possibly not to good works, so someone who doesn't do good works can't possibly have faith. So this brings works back into the picture and in fact caused the Protestants to be more moral than the Catholics. Weber explains how this high level of morality made the development of modern capitalism possible. Essentially, this morality caused a level of trust that made business easy.
The Protestant Reformation freed people from the Catholic Church and made the Enlightenment possible. This is ironic because the Enlightenment then undermined Protestantism because it undermined faith. And since the concept of good works in Protestantism is entirely dependent on the concept of faith, as soon as the Enlightenment undermined faith, the whole Protestant value fell apart. So the story of our modern world is the story Protestantism. And Liberalism is what replaced Protestantism in Protestant countries after Protestantism had been undermined by the Enlightenment.