What you are looking for cannot be provided in a short and concise answer unfortunately.
In my opinion, books aren't going to help you much, if at all. You need to build a computer yourself if you haven't already and do as much as you can to learn that way. My advice would be to pick one of those A+ certification books up (not for the cert, just for general information).
Once you have the general info down, you can start experimenting with different things.
As far as GRUB and Linux, click Here
. Start from the beginning and go to the end of the advanced courses. My suggestion would be to start with Ubuntu and then gradually increase in difficulty until you get to an operating system like Gentoo or Arch Linux.
If you have any specific questions, feel free to ask.