I suffered through this book for a world history class, it has to be one of the driest pieces of printed material I have ever laid eyes on. When I first began reading it, I thought that it might be interesting, as it focuses on how historians document history, something I've never really thought of before. But now I know why I've never thought of it. It's boring.
Perhaps this book has simply given me a poor first impression of the subject. Manning seems out of touch with anything modern(referring to 'the internet and the world wide web'), and the book generally seems outdated, though it's supposed to be an updated version of the original, which was published in 1941. Maybe there's a book out there similar to this one that is simply amazing, written by someone else for the average curious person. Though I doubt I'll go out of my way to find it.
I wouldn't recommend this to anyone, unless you're a professor or graduate student, as the book says that is its intended audience. If you're simply curious, don't waste your time.