From TV Animation - One Piece Grand Battle 2 Japan

One Piece is a long-running shonen manga series written and illustrated by Eiichiro Oda, that has been serialized in Weekly Shonen Jump since August 4, 1997. The individual chapters are being published in tankobon volumes by Shueisha, with the first released on December 24, 1997 and the 55th volume released as of September 2009. In 2009, Shueisha announced that they sold 170 million volumes of One Piece manga so far, making it the highest selling manga in history.