RFID (radio frequency identification) is a fascinating and worrisome technology. We know about it because some libraries are now using RFID chips in their security systems (to prevent books and other materials from being stolen). This article will give you an insight into the concerns associated with using the technology, as well as showing the many applications in which it is already to be found. From libraries, to retail, to health care, to the passports of the future -- is this really the direction we want to go?