I now have a whole series of "For Dummies" books. They have helped me to understand complex ideas in simple ways. However, "MODEMs for Dummies" is not worth the paper it's written on. It only contains 10 AT symbols and does not describe them very well. Of over half of this book is advertisements for various Internet services. It has a general picture of an internal modem and no comparison to external modems. There is not much more like say about this book, because there is not much more about this book!