Every UNIX Admin Group Should Have One... To loan to users
You are perceived to be a UNIX guru. People regularly come to you with great deference to ask you for advice and help. Someone apologizes for his/her lack of knowledge for the third or fourth time and asks about a basic command. You grab a thin book from the shelf. "Take a look at this book", you say, "You probably know most of what's in here, but maybe some of it will help you. Just give it back when you're done." With relief he/she clutches the book and thanks you several times. He/she almost bumps into your neighbor's cubicle wall as he/she walks away reading this book...
Buy this thin book and this may happen to you. Well, the first part you'll have to manage yourself, but no self-styled UNIX novice has been ungrateful to borrow this book. Anyone seen as a guru will find that this book will pay for itself as a time-saving loaner.
I must say, that perception plays a great deal in this case. The book is amazingly thin and sports an O'Reilly animal on the cover. Anyone in corporate IT will associate this book with the O'Reilly books the in-house experts have on their shelves. I have another book that I feel may be a bit better for UNIX beginners, but given a choice, people will grab this one.
One can't help but notice sections that are probably unnecessary for computer-savvy UNIX beginners, such as "working with a mouse" and the description of a directory structure. But these sections are brief and clear and the authors move on quickly to UNIX-specific items such as "Redirecting I/O".
I definitely prefer "UNIX: Visual QuickStart Guide" from Peachpit Press, so I'm compelled to give this book less than a perfect score. I must admit that people who borrow this book seem much more enthusiastic when they borrow it than when they return it. But they also seem ready to move on to heavier books, and that's well worth the price.