No... Aang already knew airbending before the beginning of Book !, so all they needed were three for him to learn water, earth, and fire bending
Not to mention, the entire air bending tribe is wiped out. So it would be a rather uneventful series.....
There is no book 4 of Avatar the Last Airbender.
Avatar ends in book 3
no
there is no book 4 however, they are working on Avatar: Legend of Korra
There is no Book 4, as the series ends with Book 3, but a new series will come out in 2011.
no
yes
never
yes
NO!!!!!!!!!!!There is NOT going to be avatar book 4!!!!!!!!!!BUT theres going to be another movie
there is no book 4
To be honest their will not be a book 4 of avatar the last airbender though nick staff is maybe going to make a avatar based cartoon.