I disagree. Books are invaluable resources. As good as the internet and man pages are; books will never be replaced.
This doesn't mean everything you could ever need to know is contained within some sacred tome.
A good reference will show you things you couldn't possibly have guessed at, or show you an easier way of doing something you already knew. Plus, those "writers" are usually experts in their fields. True, things may not always be complete due to the nature of the fast pace of software development, but like anything - nothing is perfect.
My recommendation is to use ALL sources of information. Whether it is a formal class, man page, online how-to, BOOK, or the guru down the street.
A good online reference...
http://www.icon.co.za/~psheer/book/rute.html.gz
When searching for books, the best method is to go to a large bookstore or library and thumb through the pages.
http://cart.cheapbytes.com/cgi-bin/cart/scan/mp=category/se=204.html?id=WmSCX7jd
Cheapbytes has a nice selection of linux books available.
http://cart.cheapbytes.com/cgi-bin/cart/0660010001.html
A great book. It's small, it's cheap, and the information is laid out in a manner that's conducive for quick reference. Not to mention that even the advanced user will likely learn something.
http://www.amazon.com/exec/obidos/t...f=sr_1_1/103-7566619-9592645?v=glance&s=books
Another useful book. Using the bash shell is something that every gnu/linux user will want/need to become proficient with. As a system administrator it behooves you to learn.
http://www.amazon.com/ Search for Linux.
Another long list of books.
Let me reiterate, if it is at all possible make a trip to the local college library or bookstore.