Now this book is a real blast from the past. I remember borrowing it multiple times from the library and reading through it multiple times (as well as a number of other books in the series, which I will get around to commenting on in time). Before I continue though I will outline one major flaw that I found in this book, and that is the question for whom the book was written. Now, as far as I can tell, this book was written for children, however there are a number of pages about buying microcomputers and accessories, and at that time (and even now) most of the products that were available were priced out of reach of the average child, and unless you had parents that were willing to fork out the cash for such machines, the chance of a child buying a computer was slim (and the friends of mine who did have computers had them because their parents, like my Dad, worked in the industry).
Now this book, as you can tell, was written in the very early Eighties, which means that they deal with computers like this:
which is a ZX Spectrum, or something like this: