This book alone wont take you to blowing the harp like a bluesman, nor will the tunes rock your friends... but it's a very good place from which to begin a journey which, if it gives you the bug, could one day lead you on to greater things. In the meantime there's plenty to enjoy as you learn. It starts at the very beginning which, as someone once sang, is a very good place to start, and if (as appears mandatory with beginner harmonica books) the first four tunes are painfully wet, at least the theory they practise is well explained.
Thereafter, what I really like about this book, amongst a handful of similarly wimpish tunes (yes "Twinkle twinkle..." really is there), at least five folk songs which are really mournful, something the harmonica does brilliantly. I was in Cornwall a fortnight back playing them from deserted clifftops out onto the Atlantic wind... I doubt it carried to Mississippi, but it felt great.
So this book isn't very rock and roll, but face it, harp wise nor are you just yet, you're thinking of buying this book because you are (like I was) an absolute beginner: the blues or rock will (I'm hoping) come one day with practice; meanwhile, unless you hate folk (in which case avoid!) there's enough good instruction and soulful music in this book (plus great CD with each tune played twice, once with the harmonica track once without) to get you hooked, at least if the harp and you are meant to be.