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