An excellent resource, which all teachers of the English language, EFL or otherwise, should give serious consideration to. Every grammatical point is extensively covered in detail (514 pages) with each area of grammar being explained expansively and broken down in it's component parts, which further outlines specific teaching points such as construction and use.
The format of the book is also excellent with an abundance of clear sub-headings, which include Key Considerations, What Is..., Consolidation Exercises, and Difficulties For Learners sections. The layout is also good and easy on the reader with large sections of text broken up with tables and bullet pointed lists and examples.
Most serious English language teachers will probably own more than one grammar refrence book, while others, such as new teachers, may only own a single book. Either way, and regardless of which category you should fall into, this book should be given serious consdideration to anyone looking to invest in a good quality grammar reference book.