Cryonics (from Greek kryos meaning icy cold) is the low-temperature preservation of humans who can no longer be sustained by today’s medicine, in the expectation they can be healed and resuscitated in the future using more advanced medical technologies. Cryopreservation of people is not reversible with current technology and is only practiced following pronouncement of legal death. The rationale for cryonics is that cryopreserved patients may retain sufficient biological and neurological structure to be restored to full physical and mental health using advanced future technologies.