Captain Underpants, Book 9 refers to one of the later installments in Dav Pilkey's wildly popular, irreverent children's series. The books star two mischievous fourth-graders, George Beard and Harold Hutchins, who hypnotize their mean principal, Mr. Krupp, into becoming the superhero Captain Underpants. This volume features a new, absurdly named villain, more crude humor, and the signature "Flip-O-Rama" interactive pages, continuing the saga of the world's least effective superhero.
