This is a wonderful and witty, practical and comprehensive guide to English grammar. From hyphens to parallel structure, this is enlightening as well as entertaining. Entertainment comes from taking down famous novelists and prominent newspapers, etc. with examples of inaccurate usage. The frequent self-tests and pretests allow the reader to gauge, and realize both deficiency and progress, but I wish the answers were on the same page. Maybe upside down at the bottom of the page. This is good to peruse or retain as a reference, as I may need to refer to it again to get the whole "who" and whom" thing straight, once and for all.
I put this right up there with The Elements of Style as a joy for reading and betterment.