Daphne West's book is an excellent reference for beginners, up to about GCSE level or equivalent (it covers most, if not all, of the required topics for GCSE). Presenting grammar rules and usages in a simple, clear and effective manner (with one particular topic per page), with exercises covering the rules on the opposing pages, 'Teach Yourself Russian Grammar' is good for grasping the basics, or for refreshing the fundamental concepts.
Its value is limited, however, much past the beginner's stage - it doesn't, for example, cover gerunds or participles, and many of the different topics fail to cover some of the more complex rules or exceptions.
If you're new to Russian, and are baffled by the seeming impossibility of the grammar, this book is invaluable, however, and is a far cry from the complex minefields contained in many Russian grammars. It is simplicity and clarity - much like the language itself when you get to know it.