I just got started to get Podcast files by iTunes a couple of years ago. At that time, I downloaded some files of the Grammar Girl that would be helpful for improving my grammar skill, I thought. I didn't realize that it would form a book, but I found that this book is published in recent and decided to buy. Well, it's not bad I think. If you start to reading this book, I'm sure to say you can enjoy reading and learning the grammar without any big trouble. It is written in a concise and informal style, so you can read it easily. But, if you want more serious and detailed one or you are a student now preparing for englsih tests like toeic and toefl, it is not appropriate, I guess.