"Secrets of the World" Book Release Party Invite

To announce the release of a book about the history of the World Theatre, we took the "Secret Society" route for the invites. Invitees had to call in to get the secret password to write on their invites and then present the invite at the door to receive the "Stamp of Approval." People didn't know it was a book release party until the "secret artifact" was revealed at the event.