A slim book that provides an excellent explanation of the English Civil Wars. If you want to understand the whys and wherefores of that period, this is for you. We see our modern ideas here and there but scattered around all parties and always bundled with what seems weird to us. Freedom of religion? Absolutely - that's provided you're not Catholic or Anglican. The book shows the whole period provides a classic example of the law of unintended consequences and reinforces the idea that Cromwell is the last person who should be commemorated outside Parliament, given his attitude towards it.
My one issue is that it's not strong on the narrative of events - you get a great explanation of why X happened, but the fact that X DID happen kind of gets taken as read. I guess if one wanted a strong narrative history as well, then the book would have got much bigger.
Buy it for an excellent, short, clear explanation - and the depressing conclusion that, in the end, nothing much came out of that period.