Originally published in French by Dargaud in 1973 under title: Philémon et le piano sauvage.
Summary
"Determined to save his friend the well-digger from the labyrinth on the second 'A,' Philemon returns to the parallel world of islands that form the words 'Atlantic Ocean.' He finds himself on the 'N' where he inadvertently breaks the law, goes on trial, and is sentenced to confront the wild piano"-- Provided by publisher.