The world outside has grown toxic, the view of it limited, talk of it forbidden. The remnants of humanity live underground in a single silo. But there are always those who hope, who dream. These are the dangerous people, the residents who infect others with their optimism. Their punishment is simple. They are given the very thing they want: They are allowed to go outside.

Darrow is a Red, a member of the lowest caste in the color-coded society of the future. Like his fellow Reds, he works all day, believing that he and his people are making the surface of Mars livable for future generations. Yet he toils willingly, trusting that his blood and sweat will one day result in a better world for his children. But Darrow and his kind have been betrayed. Soon he discovers that humanity reached the surface generations ago. Vast cities and lush wilds spread across the planet. Darrow—and Reds like him—are nothing more than slaves to a decadent ruling class.

Harry Benson suffers from violent seizures. So violent that he often blacks out when they take hold. Shortly after severely beating two men during an episode, the police escort Benson to a Los Angeles hospital for treatment. There, Dr. Roger McPherson, head of the prestigious Neuropsychiatric Research Unit, is convinced he can cure Benson with an experimental procedure that would place electrodes deep in his brain's pleasure centers.

The United States government is given a warning by the preeminent biophysicists in the country: current sterilization procedures applied to returning space probes may be inadequate to guarantee uncontaminated re-entry to the atmosphere.

A classic thriller from #1 New York Times bestselling author Michael Crichton, Sphere is a bravura demonstration of what he does better than anyone: riveting storytelling that combines frighteningly plausible, cutting-edge science and technology with pulse-pounding action and serious chills.