I started with Slackware linux its a little simpler than Debian but does not have the same support Debian has. Debian package repositories are much better than slackware.
slackware has not changed greatly over the years nor has debian the more things change the more they stay the same.
I read Linux for dummies,various redhat books when redhat company was producing commercial boxes with various versions that included cd's at electronic and book stores. one of my favorite was Linux system administration which came with slackware 3.5 on cdrom. I read Linux in a nutshell from O'Reilly which may still be in print. most of the books are probably not in print.
lots of information on linux online much more than when I started researching and learning to use linux.
I dont know whats availible on the ebook market.
when I run into a problem I use my favorite search engine and try various search strings probably easier when you know the language well no offense, otherwise I would hit a forum like Linuxquestions.org which is great resource.
http://forums.debian.net/ looks to be a good forum as well I havent used it though. may be some mIRC channels with some good help but havent used mIRC myself in years and seems to have fallen out of favor with forums and wiki's around that and mIRC was buggy and virus ridden.
if slackware interest you any which is basic linux system and one of the oldest distributions if not the oldest.
http://www.slackbook.org/
but if you want to stick with debian
http://www.debian.org/doc/
under where it says "Manuals for GNU/Linux in general" it looks like some links to online books
if ya need help with debian this list some good options
http://www.debian.org/support
in the day I read tons of How-to's but dont believe they are maintained anymore and outdate.