The Bum Trilogy consists of three books by Australian author Andy Griffiths. They are aimed at children aged around 10 and contain lots of toilet humor.
The books are named:
In the USA, the word "bum" has another meaning, so it is changed to "butt" in the versions sold there. The third book is further renamed to Butt Wars: The Final Conflict.
Griffiths' reference guide to "prehistoric bumosaurs", What Bumosaur Is That?, was published in May 2007. It is not a part of the trilogy, although the book was mentioned in the trilogy.