I bought this book several years back. The grammar that was in it was very basic and was not always helpful in understanding how to use Russian grammar properly. But if you are just starting out and you only have room to fit it in your pocket, then I'd say go ahead. But I would recommend a more comprehensive grammar book for those who want to speak a little more clearly.
From Amazon.com
A Superb Reference
This book is an excellent quick reference on Russian grammar. The information is very well organized and concise (including very useful tables of all the case endings in the back), so it's easy to find what you need very quickly. In conjunction with an English-Russian, Russian-English dictionary I can have conversations over ICQ in Russian for practice. I wish Barron's would publish these books for more languages. They are excellent for learning the language or if you're just curious about how the grammar works.