www....free-download.com/.../a-practical-guide-to-ubuntu-linux-3rd-ed\
ition.php
==The latter is direct link to .rar file.

www.freebooklinks.com/.../
http://www.ubuntupocketguide.com/index_main.html
www.onlinecomputerbooks.com/free-linux-books14.php

Others are available online, just in case the local bookstores have slim
selections.

Any reference is outdated in 6mos. This by no means should stop you from
getting one. Why not buy one from the Ubuntu web site to help with
expenses. Linux command line references can be downloaded. This list
and other user groups can answer your questions in short order. The help
file is indispensable and has a section for new Ubuntu users.
Terminology answers are best answered when you have a question, just ask
as you go along we will answer if we know.