Abstract: A mailing device is in the form of a single sheet of paper which can be folded over on itself to form its own envelope. The device is a single sheet, which may be formed with portions of different paper qualities, and is to be folded in half and then in half again to put it in a form ready for mailing. In its once folded state, the device can be printed with the necessary message using a mechanized printer, and the address of the recipient can be printed on the same surface of the device as the message, and the address will appear on the correct face of the device when it is folded again.