It is a really good book for you study English. In this book you can study how to speak English and many grammatical points of English language which are very important. This book is more than 40 mb, so it may take you a little long time to download. And the book is also designed for self-study. You can learn by yourself without any teachers to guide you because the book will be a teacher for you.
Learning a language is not an easy one. Just as said, this book is not about teaching you to be good at a specific language. Instead it targets on the people who want to learn many languages in general. Sometimes it is necessary to learn a few languaes generally. If it is the case for you this book will be particularly good for you.