The home of the actor Christopher Reeve is in the middle of horse country. He lives in Westchester County, down a winding country road that takes you past several estates with stables and riding tracks. At the end is a sprawling farmhouse set on a hill and surrounded by spruce and oak; a graded incline provides wheelchair access to the front door.

It has been eight years since Reeve broke his neck at an equestrian competition in Culpeper, Virginia. After his horse, Buck, stopped suddenly in front of an obstacle, Reeve flipped forward and suffered what doctors call a “hangman’s injury”: a fracture of the upper cervical vertebrae. Death by hanging often results from suffocation, and Reeve was heard to say, “I can’t breathe.”

The crushed vertebrae caused massive hemorrhaging within Reeve’s upper spinal cord. The location of a spinal-cord injury determines its consequences. Indeed, a minute difference in the trajectory of Reeve’s fall would have left him in dramatically different circumstances. An MRI scan that Reeve received after his accident suggested that if he had landed with his head onesixteenth of an inch to the left he would have died instantly. An impact slightly more to the right would have left him with a concussion, and he would have been back on his feet within weeks.

Reeve’s injury left him paralyzed from the shoulders down. He was unable to breathe on his own, and doctors at a Virginia hospital immediately placed him on a ventilator. Reeve was informed that his injury was permanent, and that he would no longer feel sensation in ninety per cent of his body.

Upon arriving at Reeve’s front door, I was greeted by an assistant—he employs several—and led to his office, where he sat waiting in his wheelchair. On a shelf behind him were pictures of his wife, Dana, and his three children, and a large blue button that read “proud yale parent.” His daughter Alexandra is the captain of Yale’s polo team. The Reeves are clearly not a superstitious family.

This spring, an experimental electrical-stimulation device was implanted in Reeve’s diaphragm, and he now breathes without a respirator for hours at a time, so his speech has become more fluid and his voice more resonant. He gasped only occasionally. Reeve weighs two hundred and seventeen pounds and is six feet four, and even in his motorized wheelchair he looks imposing. The most striking change in his appearance has nothing to do with his accident. Reeve has alopecia areata, a condition that causes patchy hair loss, and in February he had his head shaved.

“I was told from the very start that it was hopeless, that it was impossible for me to regain movement below the shoulders,” he began. “But every scientist should remove the word ‘impossible’ from his lexicon.” Not only does Reeve want to cure himself; he is determined to transform medical research, which he feels is constrained by excessive caution. “Research should not be reckless,” he said, but it does need to be fearless. “If you don’t add courage to the equation, the scientific aspect will go to waste.”

In his 1998 autobiography, “Still Me,” Reeve writes that he has a controlling, perfectionist nature. As an actor, he would obsessively analyze his scripts, looking for moments that could trip him up. Before the Culpeper contest, he walked the cross-country course three times and drew a map, with extensive annotations. In our meeting, he displayed a similar tendency—his words were as carefully chosen as those of a Presidential candidate.

Soon after we began talking, Dana, who is an actress, carried in a tray with some lunch—turkey with sliced cucumber. (Reeve can eat whatever he likes.) As a nurse assisted him with his meal, he described the progress he has made since he began a regular, intense physical-therapy regimen, in 2000. “I am able to use the biceps of my right arm against resistance,” he said. “My left arm is weaker. Perhaps my strongest and most remarkable recovery has been in my legs.” I noticed that his lower body did not appear to be as shrunken as that of the typical quadriplegic.

During our conversation, Reeve was largely immobile. The only movements I saw were hand gestures; he would lift his index finger and point it, often without any hesitation or visible effort. He saves greater physical exertions for his therapy sessions. I asked him if he could move his legs. “A bit,” he said, adding that he now exercised regularly in a swimming pool. “I can push myself off the side with my legs. And I can make a snow-angel movement with my arms.” The buoying effect of the water, Reeve explained, helped him make the slow, sweeping motion.

“One day, I expect to get up from this wheelchair,” he said. This claim, which Reeve has made often in speeches, has not been well received by certain scientists and advocates for the disabled. Some critics attribute his words to a state of denial; others have been more caustic, calling him a spoiled celebrity who raises false hopes. The columnist Charles Krauthammer, who is wheelchair-bound and has a medical degree, wrote an angry appraisal of Reeve after the actor appeared in a television commercial touting advances in spinal-cord research; the ad used computer imagery to make it appear as if Reeve could walk again. Calling the ad “disgracefully misleading,” Krauthammer wrote, “In Reeve’s view, reality is a psychological crutch. His propaganda to that effect undermines those—particularly the young and newly injured—who are struggling to face reality, master it and make a life for themselves from their wheelchairs.”

Reeve is aware that his intention to recover has been dismissed, even denigrated. Yet he is not as naïve as some of his doubters think. Reeve has a dogged intelligence, and in the past eight years he has developed a nuanced understanding of the biology of spinal-cord injury; he has learned how the scientific establishment sets priorities and conducts its research; and he has deciphered the ways that different branches of the government permit or bar innovative medical treatments. Reeve knows that his fame gives him unique access to the media, to politicians, and to fund-raising dollars. By exploiting these resources, he has set out to change the way things are done in the clinic, the laboratory, and the government. He believes that only by causing a revolution in all three realms does he have a chance.

It is perhaps easy to view Reeve’s quest as one driven by hubris; it is far from certain that he will walk again. However, the steady, incremental progress he has made is extraordinary and, to many scientists, confounding. Indeed, the results have been so encouraging that mainstream researchers are reconsidering the dogma that long-term paralysis is irreversible—and paralyzed patients around the world are beginning to follow Reeve’s lead.

The spinal cord is about an inch in diameter and has a soft, jellylike texture; it is protected by the long chain of vertebrae. The cord houses millions of nerves, which transmit crucial signals between the brain and the rest of the body. Extending from each nerve cell is an axon, a comparatively long, threadlike projection that can convey signals to a neighboring nerve, creating a pathway. Some of the nerve pathways that pass through the spinal cord help control muscle movements and regulate blood pressure; others allow us to feel pain, touch, and temperature.