12 books in series

Captain Underpants

Captain Underpants is a 12-book series with 12 released primary works first released in 1997 with contributions by Dav Pilkey.

Captain Underpants and the Attack of the Talking Toilets
Captain Underpants and the Invasion of the Incredibly Naughty Cafeteria Ladies from Outer Space and the Subsequent Assault of the Equally Evil Lunchroom Zombie Nerds
Captain Underpants and the Perilous Plot of Professor Poopypants
Captain Underpants and the Wrath of the Wicked Wedgie Woman
Captain Underpants and the Big, Bad Battle of the Bionic Booger Boy, Part 1: The Night of the Nasty Nostril Nuggets
Captain Underpants and the Big Bad Battle of the Bionic Booger Boy, Part 2: Revenge of the Ridiculous Robo-Boogers
Captain Underpants and the Preposterous Plight of the Purple Potty People
Captain Underpants and the Terrifying Return of Tippy Tinkletrousers: Color Edition
Captain Underpants and the Tyrannical Retaliation of the Turbo Toilet 2000
Captain Underpants and the Sensational Saga of Sir Stinks-A-Lot
The Big Captain Underpants Book O'crunchy Fun
The All New Captain Underpants Extra-Crunchy Book O' Fun 2
The Captain Underpants Annual