I will not comment too much on the content of this book - I believe that there is already substantial evidence that the content is valuable and although some may say that it is common sense, I am amazed as to how many people and writers make the simple and basic mistakes that the book points out. I bought this book to write essays for graduate schools and the principles have already proven helpful and insightful.
A quick note on the physical aspects of the book - as another reviewer pointed it, the pages do look like they were photocopied and the font type looks old-fashioned. However, for a price point of $3, there is little to complain about and if you want a better looking book (with the same content), just search for the more expensive versions of this book on Amazon.
All in all, I would highly recommend this specific version of the book if all you are looking for is the solid writing principles that the book provides.