I have been using Ubuntu for an year now and for the last 6 months I am completely on Linux(Ubuntu 8.04 then 8.10), as I go on exploring more and more about Linux I find that Linux is not an OS like Windows but more powerful and elegant than it.I came to this conclusion when I read this:
http://wiki.archlinux.org/index.php/..._afraid_to_ask(This is a wiki for how to install arch and get started in arch ).
Now when I read that I found that in Ubuntu I don't have that much independence of customizing Linux which is the main essence of Linux.
For an year I was using Linux only as a "free" OS but once I read that wiki and realized that its an OS that can be made to work just as I want.
So guys I need to learn Linux I googled a lot but didnt get any serious stuff,I mean a book or tutorial or site which preaches Linux in no nonsense manner .
If you know of any source which has serious Linux stuffs ( not how to access synaptic and click here and there but what are repos and how its made and stuffs like that I hope you understand ) please share it with me. Any help will be appreciated.
Thank You.

The Linux Documentation Project is always a good start point, as are the LQ Tutorials and the LQ Wiki. Otherwise, it's really just using it and trying to use it for specific things - whether its creating a DVD or putting a mail server together. Although learning for it's own sake can be useful, I find that things only really stick when I use them for real world reasons.

Thanks XavierP , I will surely read LDP.