Henry Haynes and the Great Escape, Paperback/Karen Inglis

When Henry Haynes complains that his new library book is boring he gets sucked down inside where Brian, a bossy boa constrictor, and Gordon, a VERY smelly gorilla, want help with their zoo escape plan. His first job: release the lions! Can Henry get home alive? And why didn't he just keep his big mouth shut about boring stories?