Although this book is really meant more as a reference tool than a revision aid, it really serves its purpose well. As a non-native speaker of Spanish, I often can't tell if I had conjugated the verb properly. I just don't have the native-speaker's kind of "intuition" when it comes to determining whether a word sounds "right" or "wrong". Anyways, I have found this book indispensable whenever I am writing essays and compositions. If you are a serious student of Spanish, you will find this book a great asset!