I pirate a lot of audio books. Or, rather, I used to. In my searches I found "A Short History of Nearly Everything". It sounded interesting so I downloaded it. I listened and heard a quality description of a number of scientific points explained in a lightly humorous and easy to understand way. So when I saw several copies of the actual book at the bi-annual Friends of the Arlington Library Book Fair I grabbed one.
This book stayed in my office and came to the bathroom with me a lot. The whole book was read two pages at a time. OK, to be fair, there were a few times I sat back and read it while the computer processed something or I waited for the printer to cough something up. I finally finished it when I had to go take a "random" drug test.
You can probably tell what I think about it from the fact that I heard it AND read it. It's good and I recommend it.
Bill Bryson, the author, isn't really a scientist. He says early on that he has the same problems that most people have with science classes and science books. He looked at a graphic in a good old 50s science text that showed a cutaway of the Earth. He wanted to know how we knew that's what it looked like. He tried looking more into the subject and found most of the literature on the subject to be cripplingly boring. He also felt that the writers were keeping the best stuff quiet.
When he first conceived of this book he was on an airplane and he realized he doesn't know why the oceans are salty but the great lakes aren't. He didn't know a proton from a protein or a quark from a quasar. How do scientists know how much the planet weighs, it's age, or what goes on in an atom. So he started this book from a position of absolute ignorance. So he spent 3 years doing research and came up with this book.
It is a very thick book and looks rather intimidating. But if you made it through Harry Potter you can make it through this. The reading levels are roughly the same. OK, this might be a bit higher. But it's not overly technical. You should also think of it as a series of smaller books. The subject areas break it down so completely that 478 pages of text are really just 7 smaller books.
Brand new this book ran about $30. This was a popular enough book that you should be able to pick up a copy in almost any used book store.