I used this book after I had learned some Spanish from tapes. I was going to a Spanish speaking country, and I needed to see what the words actually looked like, as well as to get an idea of how the language is structured. Here's the thing you need to know: although it says "Teach Yourself Spanish *Grammar*", this book is extremely useful as a practical guide to speaking the language. It's organised according to functions (for example: expressing wants, likes, giving opinions, describing the past). This makes it about a thousand times more useful than an ordinary phrasebook. A phrasebook only teaches you how to ask for, say, fruits at a market. If you're lucky, it'll teach you how to ask for vegetables too. With this book, you can just look up "expressing wants" and learn querer and preferir, and how you can use them with a noun, a verb, or a pronoun.
It's really a more "building blocks" approach to language, but it still provides sample sentences for each idea, so you can see how it's done. This book won't have you speaking fluent, advanced idiomatic Spanish (nor is it a good reference grammar for advanced learners), but it will definitely prepare you to say a wide range of things in basic Spanish.
By the way, I've lent it to two other friends who have also used it to get a basic knowledge of Spanish for reading or travel. One of them refused to give it back to me until he'd finished it!