What Ubuntu server administration books does the community recommend?
Solution 1:
The Ubuntu Server Guide(PDF) is free and written by the Ubuntu developers.
Solution 2:
I recommend the Official Ubuntu Server Book.
Solution 3:
If you work with your Ubuntu Local team you can get a free copy of the Ubuntu Server book as Jono mentioned and is posted on the Fridge here: http://fridge.ubuntu.com/node/2094.
Also I enjoyed this one: Beginning Ubuntu LTS Server Administration: From Novice to Professional even though it is a bit older