"I could hear the doctor give the order to prep me for the morgue, which was puzzling, because I had the sensation of still being alive," Ritchie said.
He even remembers rising from a hospital gurney to talk to the hospital staff. But the doctors and nurses walked right through him when he approached them.
He then saw his lifeless body in a room and began weeping when he realized he was dead. Suddenly, the room brightened "until it seemed as though a million welding torches were going off around me."
He says he was commanded to stand because he was being ushered into the presence of the Son of God. There, he saw every minute detail of his life flash by, including his C-section birth. He then heard a voice that asked, "What have you done with your life?"
After hearing Ritchie's story, Moody decided what he was going to do with his life: investigate the afterlife.
He started collecting stories of people who had been pronounced clinically dead but were later revived. He noticed that the stories all shared certain details: traveling through a tunnel, greeting family and friends who had died, and meeting a luminous being that gave them a detailed review of their life and asked them whether they had spent their life loving others.
Moody called his stories "near-death experiences," and in 1977 he published a study of them in a book, "Life after Life." His book has sold an estimated 13 million copies.
Today, he is a psychiatrist who calls himself "an astronaut of inner space." He is considered the father of the near-death-experience phenomenon.
He says science, not religion, resurrected the afterlife. Advances in cardiopulmonary resuscitation meant that patients who would have died were revived, and many had stories to share.
"Now that we have these means for snatching people back from the edge, these stories are becoming more amazing," said Moody, who has written a new book, "Paranormal: My Life in Pursuit of the Afterlife."
"A lot of medical doctors know about this from their patients, but they're just afraid to talk about it in public."
Ritchie's story was told through a Christian perspective. But Moody says stories about heaven transcend religion. He's collected them from Jews, Muslims, Buddhists and atheists.
"A lot of people talk about encountering a being of light," he said. "Christians call it Christ. Jewish people say it's an angel. I've gone to different continents, and you can hear the same thing in China, India and Japan about meeting a being of complete love and compassion."
It's not just what people see in the afterlife that makes these stories so powerful, he says. It's how they live their lives once they survive a near-death experience.
Many people are never the same, Moody says. They abandon careers that were focused on money or power for more altruistic pursuits.
"Whatever they had been chasing, whether it's power, money or fame, their experience teaches them that what this (life) is all about is teaching us to love," Moody said.
Under 'the gaze of a God'
Alexander, the author of "Proof of Heaven," seems to fit Moody's description. He's a neurosurgeon, but he spends much of time now speaking about his experience instead of practicing medicine.
He'd heard strange stories over the years of revived heart attack patients traveling to wonderful landscapes, talking to dead relatives and even meeting God. But he never believed those stories. He was a man of science, an Episcopalian who attended church only on Easter and Christmas.
That changed one November morning in 2008 when he was awakened in his Lynchburg, Virginia, home by a bolt of pain shooting down his spine. He was rushed to the hospital and diagnosed with bacterial meningitis, a disease so rare, he says, it afflicts only one in 10 million adults.
After his violent seizures, he lapsed into a coma --- and there was little hope for his survival. But he awakened a week later with restored health and a story to tell.
He says what he experienced was "too beautiful for words." The heaven he describes is not some disembodied hereafter. It's a physical place filled with achingly beautiful music, waterfalls, lush fields, laughing children and running dogs.
In his book, he describes encountering a transcendent being he alternately calls "the Creator" or "Om." He says he never saw the being's face or heard its voice; its thoughts were somehow spoken to him.
"It understood humans, and it possessed the qualities we possess, only in infinitely greater measure. It knew me deeply and overflowed with qualities that all my life I've always associated with human beings and human beings alone: warmth, compassion, pathos ... even irony and humor."
Holly Alexander says her husband couldn't forget the experience.