ubuntu vs distro

What do you think is the best book to read to study linux and what is the difference between ubuntu and distro?.. tnx..

What do you think is the best book to read to study linux ...

I don't know.  I suggest you visit amazon.com and/or barnesandnoble.com and search for books, and read reviews submitted by previous buyers.

what is the difference between ubuntu and distro?

distro is short for distribution.  The term is used to refer to any vendor's package of the Linux operating system.  Ubuntu is just one of numerous other flavors or Linux; see http://en.wikipedia.org/wiki/Comparison_of_Linux_distributions