This book is very good because it goes over each of the writing parts, one section at a time. Within the sections, they give you the specific errors and rules for grammar. The questions that appear at the end of each section and subsection (after each grammar rule) gives extra needed practice.
Reading this book, I finally got an idea of the basic writing grammar skills, and went from answering 7/14 right (in one writing section) in 25 minutes, and working with someone else, to 10/14 in 9 minutes by myself (in the same section, different questions). That's pretty good considering reading this book in less than a week.

It could have a few more problem sets like the critical reading book, and there are noticible mistakes in writing in the book. For a book that is intended to teach grammar, that's a little dangerous.

I bought all the Kaplan workbooks after I got back my March SAT scores and realized that I really needed desperate help. The Kaplan Writing Workbook 2005 was their first introduction of this series and overall it has apt-content for questions however their content review is pretty horrid.

If you really want a good overview go purchase or checkout Barron's SAT II Writing since that book is simply the best review for grammer exercises. My score went up from a 520 to a 590-710 on collegeboard exams and the Kaplan review test A placed me at a 670 so I'd tread with caution on the projected scores.

Parts of the book seem very amaeuteristic and content that an editor should have caught but nonetheless I'd say it's required for some scoring in the 500's and hoping to raise themselves to a 650+ range.