Why so worried? Just a home system? No real need to have it air tight really. Work system? Well different story then.
As RTM said do a search on google or another search engine. Go to the distro's website and read up there. Try
www.linuxtoday.com they have some ok stuff.
Look you'll never make a system that is on the net or has access to the outside world 100% safe. If someone wants in on a system they will get in on a system if they want it bad enough and know what they are doing.
There are no books that hackers use and learn from on how to hack. Yeah sure books are used, but no one book that will teach you how to become a hacker. Books can help on teaching you how to become a hacker? Well here's a few types of books I would read if I were to learn;
C++
Programming of all sorts (Perl, CGI, C, C++ and so on) whateva I needed to know.
Security books
O/S book , like Solaris books if I wanted to hack Solaris,
Expliot text found on the net about O/S's
Hacking books like hacking exposed they can be ok to get a few idea's from
The list goes on and on. Man hacking isn't something youn learn over night. Takes years to become a pro. Ok you want to stop them, but to stop them you have to think like a hacker. Man it takes practise and lots of it. Playing around with systems, courses, teaching yourself and so on. There's alot that you put into to become a hacker.
And you want to stop hackers? Well you got to be at least one step ahead of a hacker at all times to stop them.
Look if it's just for a basic home system don't bother to much about it, unless you want to learn. Me personally, I run a simple firewall at home (Zone alarm) and don't bother. Ok systems on 24/7 but I got nothing much I don't mind loosing on there. It's only a home system.
As for work different story man. I can't access net from desk computer only certain computers. The network I work on has no access to the out side world the only way to stuff it is to be on that network.