Hannam describes the lives of great scholars such as Anselm, Abelard, Averroes and Aquinas and many more. He tells of the setting up of the universities, allowing intellectual life to proceed free of outside interference. He also describes the advances in exploration and the new inventions such as the printing press. OK, so people got punished for heresy, but people have been punished for arguing against the powers that be in many societies, without the second chance that most heretics got. Hannam argues that the first glimmerings of the Renaissance were often backward steps, such as the move away from experimentation to trusting in classical authority. The book concludes with a look at the life of Galileo, showing that the church vs science aspect is a lot less clear cut that may seem to be the case.
Hannam makes a persuasive argument, but more than that, he's written a book which is enjoyable to read. I had rather expected that this book might be tough going, but found it surprisingly readable, and would recommend it to anyone with even the slightest interest in the history of science.