A book caught my attention recently with the title "How Linux Works."
Its a broad-sounding title, and thats what interested me. There are many flavors of Linux, but most of the Linux books Ive picked up tend to be tied to a particular distribution, usually Red Hat, and filled with screen shots illustrating how to use GNOME or KDE.
"How Linux Works," written by HOWTO Linux Kernel author Brian Ward, is a great resource for learning about the things that are common to all distributions, and it sticks completely to the command line.
In roughly 350 pages, the book covers all the basics, starting with the shell and ending with a great chapter about buying hardware. There are well-written sections on Samba, kernel compiling and peripheral devices in between.
"How Linux Works" costs $37.95. For more information, browse to nostarch.com/howlinuxworks.htm. Theres also a great bibliography for this book on the site.