This book is EXCELLENT. I bought myself a copy some time ago, and will use it in my home school curriculum for an 8th grader who will focus on writing this year. This book is not an in depth study of grammar, but rather a highly practical, often comical, overview of grammar, punctuation and usage. Many of the topics covered are those you encounter every time you write, which makes it still more useful. Common errors are identified. Examples are given of both incorrect and correct writing. Often the examples include "wrong," "okay," and "much better." In some sections, the informal and formal methods are demonstrated, both of which are correct, depending on the context. Reading the examples together wonderfully illustrates how to write. One is not just told, but also shown, how to do it. This book is as useful for adults as it is for kids and teens. It takes the important information needed for good writing and makes it fun and easy to remember. I highly recommend it.
I used the Easy Grammar series (which teaches, even at the elementary level, parts of speech by eliminating prepositional phrases first) for my home schooled children. Unfortunately, it is rather dry. For my 8th grader, who did Easy Grammar Plus last year, I am using Painless Grammar--a breath of fresh air--along with Easy Grammar Ultimate 180 Daily Teaching Lessons, which is a short daily review, albeit still dry. Two pages a day of Painless Grammar and one page a day of E.G. Ultimate should take about 15 to 20 minutes, leaving time for actual writing.