The second paragraph of the Preface, page xv

This guide is not intended to answer every single question you might have about Internet tools and culture. There are too many local variables that we have no way of anticipating. The Net itself changes so fast it is impossible to create a perfectly stable source of information and instruction. The best operating instructions for the Net are actually on the Net and are revised continually. We have provided information about how to find many help files and guides, but the best way to learn the technical, social, and educational ways of the Net is to dive right into it.