I am surprised that others have not found this book useful. As an English major in college (someone you would expect to have a greater-than-average grasp on grammar) I found myself lacking in a number of grammer concepts.
When you study French, you are confronted with concepts like "definite,indefinite and partitive articles". Now, in English, you will often use the article which "sounds right". This is actually when you compare your mental database of conversations,schooling, etc to the 2 or 3 options listed, and make an educated guess. Often, you can guess the right answer without actually understanding why it is the right answer, or understanding the concept behind the article.
This book is great for understanding this type of problem. The book explains what an article is (the, a , an) and how they are used in English. Then the book gives you the complementary article in French (de, de l',du) and how it is used in French.
This greatly helped my understand my native English, and how to translate my ideas into French.
The book also covers tense. Even in English, tense is not just past,present and future;tense is also ideas like "am going to go" "I was going to go" and "I am going right now".
The book covers the idea of possessive adjectives (my,yours,his), possessive pronouns (mine,yours, his) which look almost identical in English, and demonstrative pronouns like "this one" and "those/these".
However, this book is an easy read. It is not in "grammer-ese". It is well broken up, so that chapters are only 2-6 pages - enough that you can do one concept at a time.Concepts are explained very simply and examples are given that make it easy to understand.
This book is well worth buying.