Questions concerning what it takes to be the same person over time and across changes are at the heart of posthumanist fiction and central to the long philosophical tradition of asking questions about personal identity. Star Trek's Commander Riker is split in two by a teleporter accident; autobiographical memories are rewritten in Eternal Sunshine of the Spotless Mind; body parts, including sections of the brain, are replaced with machines in RoboCop; people are suspended for extended periods of time and then resurrected in A.I.; a person backs up his memory to a computer, is killed, and then lives on in the computer in Extant. In what sense are these people the same, or not the same, as the entities that preceded them and with which they are identified? If we become so enhanced or altered that we can share our experiences, survive the death of our bodies, split ourselves into multiple agents or reprogram our minds, will we cease to be persons in the future? As philosopher Allen Buchanan (2009, 349) notes, we face the possibility that "our world of persons is replaced, completely, through the sustained use of (…) enhancement technologies, by a higher sort of being, post-persons". And if these are post-persons, will it make sense to use our existing concept of personal identity in discussing them?