Debian -- Documentation
http://www.debian.org/doc/
Anything you really need for Debian can be downloaded.
"Debian GNU/Linux Reference Card
The 101 most important things when using Debian GNU/Linux"
http://people.debian.org/~debacle/refcard/
Debian GNU/Linux Desktop Survival Guide
http://www.togaware.com/linux/survivor/
"Rute User's Tutorial and Exposition"
http://rute.2038bug.com/rute.html.gz
The above should be more than enough reading to cover pretty much anything you need to know in order to run Debian GNU/Linux, or any other distro for that matter.
If you really must have hardcopy, I would suggest The Debian Bible and Rute, both can be bought at Amazon.