Did I misunderstand the question? I thought the OP wanted to learn Unix also. I'm not at all familiar, but I thought Linux was as close to Unix as the various Unixes are to each other. Anyway, if you want a book on Linux, the Ubuntu Pocket Guide gives a very good overview for someone new. You can download it free here...
http://ubuntupocketguide.com/index_main.html
It covers an older version of Ubuntu, but the core information will still apply. It'll also largely work for Debian, and Debian based distros, and with a bit of tweaking, any other Linux distro.
Edit:
Here's a small collection of books I've downloaded, and it includes the Ubuntu Pocket Guide. You should be able to find something useful in there...
http://ubuntuone.com/p/hN6/
Here's a file listing. I /think/ this is what's in there, but it's hard to say. I uploaded it awhile ago :^D
0100GS3-GettingStartedOOo3.pdf
abs-guide.pdf
cathedral-bazaar.ps
Getting Started with Ubuntu 10.04.pdf
hacker-history.ps
linux1_d50_48kbs.mp3
linux-ip.pdf
linux_starter_pack.pdf
Machtelt_Garrels_Bash_Guide_for_Beginners_2nd_Ed.pdf
portrait.pdf
refcard-en-a4.pdf
SliTaz_Review.pdf
The One Page Linux Manual.pdf
ubuntupocketguide-v1-1.pdf