The Linux Administration Handbook is a must-read for experienced sysadmins. It not only explains how to configure many different Linux services, but also gives invaluable advice on a very wide range of sysadmin responsibilities, including keeping systems secure, how to set up and maintain a server room, fixing performance problems, and managing computer systems. There are a several essential ideas that are not fully explained in the book, such as how to set up systems to shut down gracefully before an uninterruptible power supply's batteries run out, how SELinux works in detail, how to set up a hardened system, and how to set up a VPN. At least the basics of these ideas are mentioned, but a more detailed explanation of them would significantly improve the book.
This should not be your first book on system administration. The book is very dense with detailed theory of Linux system software and overarching philosophy of good system administration practices. Although this approach is ideal for the experienced administrator, it gets in the way of a beginner who is just trying to understand the basics of Linux administration and is likely struggling to get systems installed and configured properly. I would suggest one of the books by Sobell or Negus for the beginning system administrator who is more likely to need immediate how-to advice.