This is definitely the most useful book that I own. In ninth grade, my French teacher urged us to purchase this book, and so that summer I bought it. The detailed grammar section of the book was amazing, and I understood it very well without being fluent in French (though I wouldn't suggest someone with next to no French fluency to expect to understand it all). Even if you don't understand French very well, I wouldn't buy the English version; from what I've seen, it doesn't include the grammar section describing the uses and formation of verbs in their different tenses, moods, and voices. An excellent resource for the French student, teacher, or enthusiast.