Improving your grammatical skills may be very important for several reasons, one of which is to foster your overall language competence. The primary strength of this book is the fact it cotains both lucid explanations and numerous exercises to check your comprehension. In order to ensure understanding, simple explanations of rather advanced elements of grammar have been provided. By the time you master this book, you will have dramatically improved your grammatical skills. I guarantee that! Are you unsure when to use the past perfect vs past simple? What about the proper use of auxiliaries and modal verbs? Pronouns and prepositions? Gerunds and participles? Word order? Definitely a valuable book.