I found this book to be an engaging and interesting overview of events that constitute the roots of today's protestant "church". It provided me with a framework from which much "church" history can be understood. It includes Apostle Paul, papal history, Anabaptists and relationships between protestant denominations. Although lightweight in many areas, it covers a wide range of church history, which makes it very readable. Many topics may not go into as much depth as you like but there is enough to identify interest. This lack of depth is what makes the book so readable, never becoming bogged down in uninteresting topics, it keeps moving while providing stepping stones for additional reading.
What I did not like about the book is its tendency to deviate from a mostly chronological presentation. I found this was particularly annoying in the first several chapters. Later, I got use to it. There are "Protestant Pearls" (quotes) thrown throughout the book. Literally, they seem to have been thrown, having no relationship to the text. I think they should have been presented in the context of the relevant text. I would liken it to getting blips within a documentary movie have no bearing on the current scene. I found them distracting, breaking the flow so to speak. I adjusted by reading the "pearls" separately or when reviewing previously read text.
If you liked Complete Idiot's Guide to The Bible, then you'll like this one. I've known Jim Bell from his well-known Christian books, so I'm glad to see the Idiot's people have picked up one of the best for their religion books. He really breaks down what Protestants believe and why in an easy to understand way that doesn't make you feel stupid. I'm going to use this in my Bible class over the summer.