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.
All of these reviews and analysis are based on my own experiences, it will be pretty useful if you explore the book by yourselfyourself. These days people are quite busy with their own smart phones and social media activity, but I tell you what. It is a really good idea to take some time off and explore the world so you can gain better experiences of the world. The world, I meant the real world is quite bigger and broader than what the Internet world. What I meant so far is that, reading books, journals and research papers are real world experiences which may be difficult to get in online world.