Ib Penick (1930–1998), a native of Denmark, was known as "the creative mind behind the resurgence of pop-up children's books in the 1960s and 1970s. In his career, Penick designed more than 130 children's books, including Star Wars: a Pop-up Book, which sold more than a million copies. Penick related to one reporter, "...there are only about 100 folds and tricks to [his paper engineering] trade. It's like playing a piano. You have only a certain number of keys, but it's the combinations that make the difference."