The biggest bookstore in Itaewon, What The Book? has both new and used books, many of the latest magazines, and they can order any book if it is not in stock.
They are usually willing to trade old books for credit on used books, but their offers vary. Call or visit for details.
Directions: Itaewon Station exit #1. Go straight about five minutes. What The Book? is on the second floor below Wang Thai restaurant.