The steel bonnets.

Fascinating time in history, lots of primary sources and a passionate author who knows a lot about the subject matter. What's not to love?

I've seen people complain about it being too long, and I haven't read it all in one go, but I love to come back to it and I'm not in a rush. It's easy to read and in plain English (except of course when it's a letter written in 17th century dialect)