Moore, who had been in ill health, was found dead at his Dallas home. The Dallas County medical examiner's office said Moore died March 31. A cause of death was pending. A memorial service is set for Thursday in Fort Worth.
"We were Velcroed at the heart," Moore's co-author, Ron Hall, told the Fort Worth Star-Telegram. "It leaves a huge hole and void in my life. I spent the last 14 years thinking about him, worrying about him, wondering whether either I could find him or help him. It's hard to imagine that responsibility no longer being there."
The two became friends after Hall's wife, Deborah, told her husband she'd had a dream in which God told her "there was a particular homeless man, a poor man who was wise and by his wisdom our cities and lives would be changed if we could find him." The couple met Moore later after he was involved in a fight that broke out while they were serving meals at the Union Gospel Mission for the homeless in Fort Worth in 1998.
Hall recalled his wife telling him, "`That's him, that's the man I had the dream about."'
Moore was reluctant at first to befriend Hall. In their first meetings, Hall learned Moore never had attended school and had lived as a sharecropper in Louisiana before becoming a homeless drifter.
Moore also had spent time in prison. He was convicted of armed robbery in Louisiana after trying to rob a bus driver using a rusted revolver that had no cylinder. He threatened to kill the driver but left when the man said he could not get the change out of the bus till. Moore was arrested, pleaded guilty and was sentenced to 20 years in the Louisiana State Penitentiary in Angola. He was released in 1976 and went to Fort Worth, The Dallas Morning News reported.
He spent more than two decades living on the streets of Fort Worth.
After Deborah Hall died of cancer in 2000, Moore moved in with Ron Hall, and they began writing their book. Moore and Hall had delivered about 400 joint lectures nationwide after their book was released in 2006.
"He changed a lot of lives," Hall said. "People who read our book are never able to look at homeless people the same way again. He was a rock star."