Up until Nov. 10, 2008, everything in Dr. Eben Alexander's life was going extremely well.

Alexander trained at Duke University and taught at Harvard University. He was a respected and successful neurosurgeon.

"It was all thrown into a corner with a very severe form of bacterial meningitis," Alexander says. "But it turned out to be very fortunate."

At about 5 a.m. on that date, Alexander awoke with early symptoms of bacterial meningitis. As his case progressed, the illness became extremely severe.

Alexander was admitted to Lynchburg General Hospital in Virginia, where he worked. Doctors diagnosed him with a type of bacterial meningitis that mostly attacks newborns.

"One in 10 million cases are diagnosed in a year," Alexander says. "It is very rare."

E. coli bacteria had penetrated Alexander's cerebrospinal fluid and literally was eating his brain. His chances for survival were very low, and soon became nearly nonexistent.

Alexander was so sick, his cerebrospinal fluid dropped from its normal 60-80 to 1. All exams showed severe cortical damage, and he says today his neocortex was "trashed."

Bacterial meningitis had done such severe damage to his neocortex, doctors believed that even if he survived, the prognosis was that Alexander would likely be in a permanent vegetative state for the rest of his life.

For seven days, he lay in a coma. During this ordeal, Alexander's entire cerebral cortex shut down and the part of his brain responsible for all higher neurological function went dark.

On the seventh day, as his doctors debated whether to continue treatment or just let Alexander die, his eyes popped open. No one questions that was a medical miracle.

"None of my doctors could explain how I spent seven days in a coma, yet recovered completely in just three months," Alexander says. "The explanation came after more than three years of intense research and study."

To observers, Alexander seemed to be locked away in darkness in that coma. But inside his mind, he remained fully conscious, journeying to what he describes as a world of beauty, peace and unconditional love.

Most near-death experiences, or NDEs, are the result of cardiac arrest when the heart stops pumping blood to the brain, which then becomes deprived of oxygen and can no longer support consciousness. That doesn't mean the brain is truly dead, but Alexander believes his was.

His synapses, which support the electrochemical activity that makes the brain function, were stopped. Alexander's own doctors told him that all the brain tests they gave him showed that his vision, hearing, emotion, memory, language and logic could not have been intact.

What surprised Alexander most of all was that he could remember what he experienced during the coma, even though he had lost memories of his life before he was sick. He calls his coma experience "hyper-real."

"The intensity of the meningitis was so severe, I really had no memories at all," Alexander says. "The important thing has been trying to get to back to where I was.

"The first to come back were words and language," he says. "Then it was memories of childhood.

"But the memory of what I saw in coma remained crystal clear," he says. "One of the very striking features of those memories is that they do not fade. They are solid as a rock and just as fresh now as the day I experienced them."

Alexander grew up a Methodist, raised in a religious home in Winston-Salem, N.C. In 2000, he began losing his faith, especially his faith in prayer.

Today, Alexander says he will never doubt that there is an omnipotent God of unconditional love. Although there may be doubters and critics, Alexander firmly believes what he saw was real.

Alexander found himself in a primitive world, where he was guided by a spirit that appeared as a beautiful girl with high cheekbones and blue eyes, dressed in a peasant dress.

Without speaking, she gave him a message in three parts: "You are loved and cherished, dearly, forever," "You have nothing to fear," and "There is nothing you can do wrong."

"I found out later that the girl in the peasant dress was my long-lost sister," Alexander says. "For so many readers, that image clinches it.

"I knew I'd never met her in my life," Alexander says. "I remember everything, from how she was sitting to what she was wearing and how she looked at me."

Others can have such an experience, but they don't have to die to do it, Alexander says. He practices deep meditation and sacred acoustics to keep in touch with the world he discovered.

"I meditate several times a day," Alexander says. "I do recommend a very strong and solid professional to help."

The views of scientists in fields such as physics and chemistry can be "woefully inadequate," Alexander says.

"In medicine, we are going to get back to the real," he says. "We have a very powerful, loving God.

"After the coma, this has really become my life's mission," Alexander says. "It's to tell people it's really about spirituality."

Nothing else can explain his situation, Alexander says.

"At the time I got sick, I was coordinating medical research worldwide," he says. "I was back full-time at that work within three months of my illness."

True NDEs involve the brain, not the heart. Although many people believe a non-beating heart defines clinical death, it's actually the cessation of brain activity that determines that, Alexander says.

Permanent damage to brain cells begins after four minutes of zero blood flow. Suffering cardiac arrest and then being revived can do little damage to the brain, compared to a week in deep coma with bacterial meningitis.

Loss of consciousness for hours or days bring a patient close to death. Meningitis is especially severe because it can destroy the neocortex, or outer surface of the brain.

Alexander believes his full recovery not only is a miracle, but it happened for a reason: The chance to share his experience with others.

Today, he is convinced that the mind and consciousness can exist without the brain. In other words, after death, the soul lives on.

Furthermore, he believes that neuroscientists and physicists are going to come around to acknowledge these phenomena in the next few years.

While thousands of people have had near-death experiences, most scientists argue that they are simply fantasies, the result of extreme stress put on the brain as a person is dying. True glimpses of heaven are impossible, they say.

But for Alexander, the real miracle had already happened while he in the coma. He says he journeyed beyond the physical world, encountering an angelic being that guided him.

In an instant, Alexander had gone from not believing in heaven, God or the soul to his theory that true health can be achieved only when we realize that God and the soul are real and that death is not the end, but rather a transition.

Today, Alexander believes a revolution in medicine in which science and spirituality both thrive is inevitable. Scientific and religious leaders must be open to understanding this truth, he says.

The idea that science and spirituality are separate is "primitive and simplistic," Alexander says.

"A division between science and spirituality is false," he says. "So is a division between religions.

"They converge over the one truth: The reality of our eternal soul. There is a false sense of boundaries."

But for a time, Alexander doubted himself.

"I was my own worst critic for a long time," he says. "I told my son, Eben IV, who was studying neuroscience at the time, who has also been a tough critic, that it was way too real to be real.

"I told him, 'I think it had to be some kind of bizarre hallucination, an effect of the drugs.' But I eventually came to realize there was a deeper truth that allowed such an experience to unfold."

Colleagues who helped Alexander were critical but open-minded.

"So many nurses in the ER or hospice know it's real for a fact because they see so many deaths," he says. "Neuroscience that does not recognize consciousness is still at the kindergarten level."

Originally, Alexander planned just to write a scientific paper about his experience, but decided he needed to reach out to the public. On Oct. 23, 2012, his book "Proof of Heaven" was published and leapt to the top of the New York Times bestseller list, where it remained for months.

It is lay people who are most likely to believe.

"That's why the book has had such an impact on the world," Alexander says.

Readers can expect a sequel to "Proof of Heaven."

"Only one-third of the memories are included in the book," Alexander says. "I knew going in that to present it in its entirety would mean some of it might be left out. That's why I will be writing additional books."