Well I personaly started of with Linux after having used Win for most of my life...
Harnessing the Powers of Linux (and I really mean making it work like YOU want it to work) is a good starting point.
For Security I liked the "Maximum Linux Security" (can be bought from Amazon) quite well ...
If you don't known networks though it's a bit tough!
For Networks try the "Linux Network Administrators Guide"
It's not too tough and gives you a good introduction.
I personaly have a network with about 8 Computers at home and use that to set up different networks and try stuff...
Like adding this to ipchains breaks that...
Hope this helps!
