From the Book - 6th edition.
Book 1: Getting started with Linux
Troubleshooting and configuring Linux
GNOME and its derivatives
Navigating the Linux file system
Introducing Linux applications
Connecting to the Internet
Setting up a local area network
Hosting Internet services
Introducing basic system administration
Managing users and groups
Working with Samba and NFS
Introducing Linux security
Vulnerability testing and computer security audits
Introductory shell scripting
Working with advanced shell scripting
Book 8: Linux certification
Studying for the Linux Essentials certification exam
Studying for the CompTIA Linux+ Powered by LPI certification exams
Other Linux certifications.