''I hope that friends and fans of Johnny will pray for the Cash family to find comfort during this very difficult time,'' Robin said.
Cash's death came just four months after the death of June Carter Cash, his wife of 35 years.
Cash -- known to fans around the world as "The Man in Black" -- had battled several serious health problems over the past few years, including a disorder of the nervous system, autonomic neuropathy, and pneumonia. He had been discharged from the hospital Wednesday, following a two-week stay for treatment of an unspecified stomach problem. That illness caused him to miss the recent MTV Video Music awards, where his video "Hurt" was honored for best cinematography.
Ed Benson, executive director of the Country Music Association, called Cash an "international ambassador of country music" who would be sorely missed.
"He was not only a giant in the music business but a cultural icon," said Benson.
Cash -- who recently added four more CMA Award nominations to his extensive list of honors -- has won six CMA Awards, including Entertainer of the Year in 1969. He was a member of the Country Music Hall of Fame, the Songwriters Hall of Fame and the Rock and Roll Hall of Fame. He also was honored with a star on the Hollywood Walk of Fame, an Academy of Country Music Pioneer Award, numerous American Music Awards and a Gospel Music Dove Award.
Cash won 10 Grammy Awards, including one in 2002 for "Give My Love to Rose" and one in 2000 for "Solitary Man." His "Unchained" won for Best Country Album in 1997, and he won for Best Contemporary Folk Album in 1994 for "American Recordings."
Two of Cash's duets with June Carter Cash -- "Jackson" and "If I Were a Carpenter" -- won Grammys, and Cash won Grammys for "A Boy Named Sue" and "Folsom Prison Blues."
"I Walk the Line," "Ring of Fire" and "Folsom Prison Blues" are in the Recording Academy Hall of Fame, and the academy honored Cash with its Lifetime Achievement Award im 1999.
"If country music is the poetry of America's common man, then surely Johnny Cash is its poet laureate," said the Kennedy Center for the Performing Arts in a statement when Cash received a Kennedy Center Honor in 1996. "Through words and music, for nearly half a century, he has expertly captured the moods, the thoughts, the struggle of the American working people -- the farmers, the truckers, the factory workers."
Rodney Crowell -- who was married to Cash's daughter, singer Roseanne Cash, from 1979-92 -- said he was "deeply saddened" by Cash's death.
"As a musical hero to millions, a trailblazing artist, humanitarian, spiritual leader, social commentator and most importantly, patriarch to one of the most varied and colorful extended families imaginable, Johnny Cash will, like Will Rogers, stand forever as a symbol of intelligence, creativity, compassion and common sense," said Crowell. "I'm thinking Mount Rushmore."
"It's a sad day in Tennessee, but a great day in Heaven," said Merle Kilgore, who co-wrote "Ring of Fire" and was best man at Cash and Carter's wedding. "The 'Man in Black' is now wearing white as he joins his wife June in the angel band."
Producer Dick Clark remembered Cash as an American original.
"Johnny Cash made an indelible mark on rock 'n' roll and country music," said Clark. "No one will ever forget his signature voice"
Sam Lovullo, the producer of the long-running country music TV show "Hee Haw," said Cash was irreplacable.
"We've lost a giant in the music business," said Lovullo, "and I have reason to believe that nobody's going to come along to fill his shoes."
Singer Jessi Colter, the widow of the late country star Waylon Jennings, said she would always treasure her friendship with Cash.
"While it's sad that we lost him," said Colter, "there's a part of me that's feeling a little joy in knowing that his soul is finally released."
Cash conquered the poverty he was born into on a sharecropper farm during the Depression, and the drug addiction he developed after he became a star, to carve out a legendary career and become an elder statesman of country music.
With his smoky, rumpled baritone, he turned out hit after hit from the brooding "Ring of Fire" and the rowdy "Folsom Prison Blues" to the plainspoken romanticism of "I Walk the Line" and the comic delight, "A Boy Named Sue."
"If anything," he told an interviewer in 1998, "I'm not a singer. I'm a song stylist."
After his autobiography was published in 1997, Cash revealed he had been diagnosed with autonomic neuropathy. The disorder made him susceptible to pneumonia -- for which he had been hospitalized several times since 1998. He was hospitalized in October 2001 with bronchitis.
Born Feb. 26, 1932, in a dirt shack in Kingland, Ark., Cash began working in cotton patches when he was old enough to handle a hoe and was hauling water for road gangs by the time he was 10.
At 12, Cash began writing songs like the ones he heard on hard country music stations.
"I picked cotton until I was 18 years old," Cash said. "Then, I picked a guitar and I've been picking it since."
Cash bought his first guitar in Germany, where he served in the Army during the Korean War. While teaching himself to play, he wrote "Folsom Prison Blues."
After his discharge from the service, Cash moved to Memphis, Tenn., where he married his first wife, Vivian. He took a course in radio announcing and met guitarist Luther Perkins and Marshall Grant, a bass player.
Their early work as Johnny Cash and the Tennessee Two was rejected as "too country" by Sun Records, the firm that pioneered Elvis Presley. When Presley left for RCA and international stardom, Sun's legendary Sam Phillips signed Cash.
In June 1955 the trio came out with "Hey, Porter" on one side and "Cry Cry Cry" on the other, both written by Cash. The tunes quickly were followed by the classics "Folsom Prison Blues" and "I Walk the Line," which crossed over to become a pop hit for Cash.
The popularity of "Folsom Prison Blues" among prison inmates led to speculation that Cash himself had done time. He told an interviewer the song was inspired by the 1951 movie, "Inside the Walls of Folsom Prison."
"I saw the movie, liked it and wrote the song," he said. "That's all there was to that."
During the 1950s and 60s, Cash struggled with depression and drug dependency. The pressure of success and the death of his friend Johnny Horton in a car accident in 1960 hurled Cash into a serious depression.
He became increasingly dependent on amphetamines and barbiturates. He missed concerts and sometimes appeared on stage for performances that were not first quality. He was arrested in Texas on Oct. 6, 1965, for smuggling pep pills into the United States. He was fined $1,000 and given a year on probation.
Some of Cash's friends wondered if he would ever make a comeback.
With the help of June Carter, former Tennessee Health Commissioner Dr. Nat Winston and his mother's religious faith, Cash survived to make a comeback in the 1970s and 1980s.
Cash had separated from his first wife in the mid 1960s, and rumors circulated about his relationship with June Carter, daughter of Mother Maybelle Carter of the legendary Carter family. June Carter had been on Cash's road show since the 1960s. She agreed to marry him if he kicked his drug habit.
Cash said he locked himself in an upstairs bedroom "so the pushers and creeps" could not get to him.
"I climbed the walls for two weeks," said Cash. "At the end of 30 days Nat said, 'I didn't think you were going to make it, but now I think you are.'"
It was during this time that some of his most notable songs were written and recorded, including "In the Jailhouse Now," "Understand Your Man" and "The Ballad of Ira Hayes."
Cash starred in "The Johnny Cash Show," a variety show that ran from 1969-71 on ABC. He also headlined his own show on CBS in 1976. Cash -- who frequently donated his talents to charitable enterprises, particularly to prison groups -- toured in the late '80s and early '90s with Jennings, Kris Kristofferson and Willie Nelson as "The Highwaymen."
Cash also appeared in numerous dramatic roles in movies and television, including the Westerns "The Gunfight" (1971) and "The Last Days Of Frank and Jesse James" (1986). In addition, he wrote the scores for the feature "Little Fauss and Big Halsy" and the TV movie "The Pride of Jesse Hallam (1980).
Cash had four daughters by his first wife, including Roseanne. He and June Carter Cash had a son, John Jr.