Cryonics involves the cryopreservation of humans as soon as possible after legal and clinical "death". Legal and clinical death differ importantly from biological death or true (irreversible) cessation of function. It is therefore a mistake to portray cryonics as an alternative to cremation or burial. It is true that cryopreserved people are not alive but neither are they dead. Cryonics should be seen as part of the field of life extension. Cryonics enables the transport of critically ill people through time in an unchanging state to a time when more advanced medical and repair technologies are available. Even after "longevity escape velocity" has been attained and aging has been largely tamed, cryonics will continue to be needed for people who die of accidents or diseases for which there is no cure at the time.