If you have the slightest interest in Unix system administration, you NEED this book... it will either equip you for the job or make you consider a new line of work.
This book is by far the best book out there for general UNIX system adminstration. The third edition is even better than the second. Whereas the second edition sometimes got bogged down in trying to mention too many different UNIX flavors, this new addition just concentrates on four main ones (HP-UX, Solaris, Red Hat Linux, and BSD). An excellent decision because it nows has great details and specifics about the four types. An excellent reference and it's entertaining to read too! Highly recommended.
I only regret that the author Evi Nemeth is disappeared en route between New Zealand and Australia on her 40-foot sailboat Wonderland.