To quote the back cover:
If you are new to UNIX, this concise introduction will tell you just what you need to get started, and no more. Why wade through a 600- page book when you can begin working productively in a matter of minutes?
The answer is very simple, you will very soon need to know more, particularly if you having to be your own system manager. This book is rather expensive for what is, to all intents and purposes, only the first section of a much larger book. A quote from the first couple of pages should settle the issue in most minds:
Otherwise, browse through the next few sections and find the one that applies to you. (We can't cover every user's situation exactly. If none of these suggestions helps you enough, ask another UNIX user or your system administrator.
If you had such help to hand why would you be learning to login from a book?