Mary Stuever knows she is passing through an invisible barrier as a light suddenly shines all around, becoming brighter and brighter. Radiant beams like those of the sun fill the entire space of the car and invade the 60-year-old’s frail body. At the same instant, a sound like a jet airplane vibrates in her ears while resonating inside her being. The air is completely still.

Waves of love and joy begin to accompany the light. Caught up in the moment, Stuever is only aware of this reality. The flood of emotions are so strong they are almost unbearable. This pleasure is greater than any human love she has known. Stuever wonders, is this God?

The noise and feelings stop. Everything seems to be going backwards, like a movie in rewind. Stuever realizes she has been in a car accident. With an air bag in her face and her body numb from shock, her nostrils inhale the strong stench of gasoline. Then, as if coming out of a dream, she remembers filling up the gas tank just before being hit. Stuever must get out of the car.

It will be years before Mary Stuever understands that she is one of an estimated 13 million Americans who have experienced a near death experience (NDE), according to a 1992 Gallup Poll, the latest survey on the topic conducted.

“(NDEs) are peoples’ reported memories of what are usually a vivid experience of an altered reality,” explains Janice Holden, the president of the International Association of Near Death Studies (IANDS).

According to IANDS, there are two types: a pleasurable NDE and a distressing NDE. Stuever explains that her NDE was pleasant and does not remember the actual car accident occurring, only the aftermath. Studies conducted by IANDS show that most people who have a NDE have feelings of love, joy or peace, rather than distressing feelings, like terror, anger or guilt.

“People can have NDEs under many conditions and there are many different causes,” says P.M.H. Atwater, a longtime researcher of NDEs and author of several books, including the “Complete Idiot’s Guide to Near-Death Experiences.”

Barry S. Rothman, a Professor of Biology at SF State, says he cannot explain some of the paranormal experiences that many people recount. But he does believe we have brain circuitry that is activated when we're convinced we are about to die, which can produce the typical "near-death” experience. Often the sense of euphoric calm and clarity people have about what is unfolding is all in their heads, with no supernatural forces being invoked.

A loud knock on the door stirs Michael Geymont, 33, out of bed at 1:30 a.m. His girlfriend urges him not to get up. Compelled to answer, Geymont opens the door to a gun in his face. In self-defense, he tries to grab the gun from the man holding it, but it goes off, shooting him in the hand. After six more shots he is down, fighting to take a breath.

Moments later, when flying in a medic helicopter, Geymont had a NDE.

According to IANDS, a pleasurable near death experience goes through four phases. The first is disassociation, when a person no longer feels connected with his body or a particular perspective. After this is the naturalistic phase, where a person becomes aware of his surroundings and that he is looking down at his own body. Next is the supernatural phase, when contact and interaction is made with a world other than earth – this is when the person sees beings of light and is exposed to paranormal activity. The final phase of a NDE is called a return, when the person comes back into his physical body.

Geymont says this took place abruptly. One moment he was watching the doctors work on his body and then as soon as they placed the defiblirator paddles on his chest he was back inside.

“I felt like I got hit with a baseball bat and then I was back in my body, it is really hard to explain,” says Geymont.

It wasn’t until after his NDE that Geymont started to read books on physics and religion.

“Typical reactions to a NDE include the person becoming more caring towards people, more interested in spirituality, and sometimes religion,” says Holden.

Since Stuever’s accident 10 years ago, she has started to explore the spiritual realm by going to conferences to learn about healing. While living in Chicago, she became a member of Mystical Science Institute before moving to Stockton, Ca. in 2004. Since then, she has started meeting with a local Bay Area group for people who have had a NDE. Nadia McCaffrey is the coordinator of the meetings and has had three NDEs of her own, the first occuring when she was only 7-years-old.

After being bit by a poisonous snake, McCaffrey was in a coma for 10 days, in which she left her body and encountered “a beautiful lady of light.” Since then, McCaffrey has had a hard time integrating back into society.

“You don’t just have one (a NDE) and forget about it, you will encounter physical changes at a cellular level,” says McCaffrey.

She attempted suicide twice later in life, surviving both episodes and again having near-death experiences. Since the supernatural moments in her life, McCaffrey has become a spokesperson for NDEs. She also started Angelstaff, a group of volunteers who go to the bedsides of the terminally ill and dying. It is McCaffrey’s hope that, since she has been on the other side of death, she can comfort others who are about to die.

“A NDE takes away the fear of life and death and if you are not afraid of dying you have a greater chance to live,” McCaffrey says.