Dozens of people are being stored in cryonic facilities. Probably the most famous of them is baseball legend Ted Williams (see below). But no one has actually been revived, because the technology to do so still does not exist.
Critics say companies that perform cryonics are simply bilking people out of their money with the promise of an immortality they cannot deliver. Even scientists who perform cryonics say they haven't successfully revived anyone -- and don't expect to be able to do so in the near future. One of the problems is that, if the warming process isn't done at exactly the right speed, the cells could turn to ice and shatter.
Even though people in cryonic suspension haven't yet been revived, living organisms can be -- and have been -- brought back from a dead or near-dead state. Defibrillators and CPR bring accident and heart attack victims back from the dead on an almost daily basis. Neurosurgeons often cool patients' bodies so they can operate on aneurysms -- enlarged blood vessels in the brain -- without damaging or rupturing them. Human embryos that are frozen in fertility clinics, defrosted and implanted in a mother's uterus grow into perfectly normal human beings.
Cryobiologists are hopeful that a new technology called nanotechnology will make revival a reality someday. Nanotechnology uses microscopic machines to manipulate single atoms -- the tiniest units of an organism -- to build or repair virtually anything, including human cells and tissues. The hope is that, one day, nanotechnology will repair not only the cellular damage caused by the freezing process, but also the damage caused by aging and disease. Some cryobiologists predict that the first cryonic revival might occur somewhere around the year 2040.