The format of the book is helful for the independent learner, but might not be as useful for one who doesn't have the motivation to continue studying on their own. As with any language, you learn best by using it in in everyday speech, and unless you have a partner to study with, or are taking a spanish course of some sort, the book might have limited uses.

I haven't used the companion CD's which cover pronunciation and allow you to get the ear training done, but would assume that they are as good as the ones which are a part of the Basic Spanish Grammar book, also by Ana C. Jarvis. If this book is used with Basic Spanish Grammar, you should have no problem acquiring the basic knowledge which will set you well on your way to becoming a fluent speaker of spanish. Or at least it'll ensure that you'll know enough to get along...