The live-in customers at the Alcor Life Extension Foundation here reside in eight 10-foot-high steel tanks filled with liquid nitrogen. They are incapable of breathing, thinking, walking, riding a bike or scratching an itch. But don’t refer to them as deceased.

They may be frozen at minus 320 degrees Fahrenheit and identified by prisonlike numbers. But to Alcor, the 67 bodies – in many cases, just severed heads – are patients who may live again if science can just figure out how to reanimate them….