Wired is running a photo essay on cryonics, the low-temperature preservation technique that intends to preserve the structure of the mind sufficiently well for patients to be restored to life by future technology:

The Prospect of Immortality is a six-year study by UK photographer Murray Ballard, who has traveled the world pulling back the curtain on the amateurs, optimists, businesses and apparatuses of cryonics.

"It's not a large industry," says Ballard, who visited the Alcor Life Extension Foundation in Phoenix, Arizona; the Cryonics Institute in Detroit, Michigan; KrioRus in Moscow, Russia; and Suspended Animation Inc in Boytan Beach, Florida; among others.

Cryonics is the preservation of deceased humans in liquid nitrogen at temperatures just shy of its boiling point of -196°C/77 Kelvin. Cryopreservation of humans is not reversible with current science, but cryonicists hypothesize that people who are considered dead by current medical definitions may someday be recovered by using advanced future technologies.

Stats are hard to come by, but it is estimated there are about 2,000 people signed up for cryonics and approximately 250 people currently cryopreserved. Over 100 pets have also been placed in vats of liquid nitrogen with the hopes of a future recovery.

Link: http://www.wired.com/rawfile/2012/10/murray-ballard-cyronics/

Source:
http://www.fightaging.org/archives/2012/10/a-cryonics-photo-essay-at-wired.php