UNIX

• The Linux Users' Guide
• Installation and Getting Started Guide
• Linux From Scratch
• Advanced Bash Scripting Guide
• Linux 2.4 internals
• The Linux Cookbook: Tips and Techniques for everyday use.
• The Linux System Administrator's Guide
• Linux Consultant's Guide
• Securing and Optimizing Linux Red Hat Edition - A Hands on Guide
• The Linux Network Administrator's Guide
• Linux Administrator's Security Guide
• Linux System Administration Made Easy
• The Linux Kernel Module Programming Guide
• The Linux Programmer's Guide
• The Linux Kernel Hackers' Guide
• The Linux Kernel.
• Slackware Linux Unleashed
• Linux System Administrator's Survival Guide
• RedHat Linux Unleashed
• UNIX unleashed

• The Linux Documentation Project HOWTOs on The Linux OS.
• The Linux Documentation Project HOWTOs on System Administration and Configuration.