This book, written by real Linux professionals Evie Nemeth, Garth Snyder and Trent Hayne, can be considered a desktop guide for a professional Linux system administrator, which discusses the installation, deployment, configuration and maintenance of systems of any complexity level. Systems under consideration include Red Hat Enterprise Linux, Fedora Core, SUSE Linux Enterprise, Debian GNULinux, and Ubuntu Linux. The book contains many practical examples and tips. The use of Linux in commercial companies, government agencies, universities is being considered, therefore, some experience with this operating system is required to read the materials of the publication. The emphasis in the book is on the presentation of issues related to the operation of Linux systems in networks (local networks, the Internet) - the most complex aspect of system administration. The book is aimed primarily at information technology professionals, but it will also be useful for beginners interested in Linux system administration.