A somewhat nebulous title doesn't prevent this from being a good book. Lewis has obviously been using Linux for a long time and is very knowledgeable. Here are the topics he covers.
Table of Contents:
1 Using the Terminal / Command Line 2 The Desktop 3 Files and Directories 4 Networking and the Internet 5 Permissions, Access, and Security 6 Processes 7 Disks and Partitioning 8 Working with Scripts 9 Automating Tasks Using Cron 10 The Kernel Appendix A: Linux Best Practices Appendix B: Finding Help Appendix C: Index
Like him, I've been working with Linux a long time, so this was more of a refresher than training. I read the book on my subway ride to and from work each day over the course of several months (mixed in with several other books I have on the go). I was pleasantly surprised at how much I learned on a number of different topics. Probably the most helpful was the section on LVM, which I admit to being a newbie to. Being a relatively complex subject, the chapter on LVM is more of an overview than in depth, but nevertheless a great entry point.
The book isn't without flaws: one bizarre suggestion that stuck with me was given in the kernel chapter, where he explained that he unpacked the kernel source and built the kernel under the /tmp/ directory because (if I recall correctly) he likes short path names. That's all fine and good ... right up until the next reboot, at which point most Linux-based OSes will wipe /tmp/ completely clean. Thus removing all your hard work tweaking the kernel config.
The topics are somewhat diverse, but if you're command line oriented, it's a very good general introduction or refresher course.