Bum Books in Order

The Bum, or Butt, books take one very simple idea and run with it as far as possible: what if your backside decided it was tired of taking orders and ran away? Twelve-year-old Zack Freeman wakes up to find his bum has literally detached itself and is plotting revolt.

In The Day My Bum Went Psycho Zack learns that rogue bottoms everywhere are preparing to overthrow their owners by unleashing a gigantic methane explosion from the legendary Bumcano. Alongside veteran bum-hunter Silas Sterne and his daughter Eleanor, he has to cross deserts, forests and some very smelly terrain to save both his dignity and the world.

The sequel, often titled Zombie Butts from Uranus! in North America, pushes the joke into outer space, with radioactive undead backsides heading for Earth and Zack reluctantly dragged back into battle. The final book, published in some places as Butt Wars: The Final Conflict or Bumageddon, turns the fight into an all-out intergalactic war with flying bum squadrons and villainous prehistoric behinds.

Between all the fart jokes and wordplay, the trilogy works like a fast-paced adventure series. There are training scenes, secret organisations, big set-piece battles and villains who are ridiculous but still dangerous. Terry Denton's illustrations keep the tone light, but the stakes are always surprisingly high.

A spin-off guide, What Buttosaur is That? or What Bumosaur is That?, imagines a whole fossil record of prehistoric bumosaurs. It gives fans even more ridiculous detail about this odd little universe and shows how committed Andy Griffiths is to following a silly idea all the way to its most absurd conclusion.

These books are especially popular with kids who claim they do not like reading. The promise of pure toilet humour gets them to open the first page, and the wild, cartoon action keeps them turning the rest.