ACCLAIMED as the "King of Pop" and later derided as "Wacko Jacko," Michael Jackson was pop music's undisputed mega star who fell from grace. Lynn Elber looks at his bizarre life.

Michael Jackson, the late "King of Pop" who once moonwalked above the music world, was preparing for a comeback tour to vanquish nightmare years of sexual scandal and financial calamity.

He performed in Taiwan in the 1990s, but had never made it to the Chinese mainland.

He was just 50 when he died of apparent cardiac arrest on Thursday at his home in Los Angeles.

Jackson's death brought a tragic end to a long, bizarre, sometimes farcical decline from his peak in the 1980s, when he was popular music's premier all-around performer, a uniter of black and white music who shattered the race barrier on MTV, dominated the charts and dazzled even more on stage.

His 1982 album "Thriller" -- which included the blockbuster hits "Beat It," "Billie Jean" and "Thriller" -- is the best-selling album of all time, with an estimated 50 million copies sold worldwide.

At the time of his death, Jackson was rehearsing hard for what was to be his greatest comeback: He was scheduled for an unprecedented 50 shows at a London arena, with the first set for July 13.

As word of his death spread, MTV switched its programming to play videos from Jackson's heyday. Radio stations began playing marathons of his hits. Hundreds of people gathered outside the hospital. In New York's Times Square, a low groan went up in the crowd when a screen flashed that Jackson had died, and people began relaying the news to friends by cell phone.

"No joke. King of Pop is no more. Wow," Michael Harris, 36, of New York City, read from a text message a friend had sent him. "It's like when Kennedy was assassinated. I will always remember being in Times Square when Michael Jackson died."

The public first knew him as a boy in the late 1960s, when he was the precocious, spinning lead singer of the Jackson 5, the singing group he formed with his four older brothers out of Gary, Indiana. Among their No. 1 hits were "I Want You Back," "ABC" and "I'll Be There."

He was perhaps the most exciting performer of his generation, known for his backward-gliding moonwalk, his feverish, crotch-grabbing dance moves and his high-pitched singing, punctuated with squeals and titters.

His single sequined glove, tight, military-style jacket and aviator sunglasses were trademarks, as was his ever-changing, surgically altered appearance.

"For Michael to be taken away from us so suddenly at such a young age, I just don't have the words," said Quincy Jones, who produced "Thriller."

"He was the consummate entertainer and his contributions and legacy will be felt upon the world forever. I've lost my little brother today, and part of my soul has gone with him."

Jackson ranked alongside Elvis Presley and the Beatles as the biggest pop sensations of all time. He united two of music's biggest names when he was briefly married to Presley's daughter, Lisa Marie, and Jackson's death immediately evoked comparisons to that of Presley himself, who died at age 42 in 1977.

As years went by, Jackson became an increasingly freakish figure -- a middle-aged man-child weirdly out of touch with grown-up life. His skin became lighter, his nose narrower, and he spoke in a breathy, girlish voice.

He often wore a germ mask while traveling, kept a pet chimpanzee as one of his closest companions, and surrounded himself with children at his Neverland ranch, a storybook playland filled with toys, rides and animals. The tabloids dubbed him "Wacko Jacko."

"It seemed to me that his internal essence was at war with the norms of the world. It's as if he was trying to defy gravity," said Michael Levine, a Hollywood publicist who represented Jackson in the early 1990s. He called Jackson a "disciple of P.T. Barnum" and said the star appeared fragile at the time but was "much more cunning and shrewd about the industry than anyone knew."

Jackson caused a furor in 2002 when he play fully dangled his infant son, Prince Michael II, over a hotel balcony in Berlin while a throng of fans watched from below.

In 2005, he was cleared of charges he molested a 13-year-old cancer survivor at Neverland in 2003. He had been accused of plying the boy with alcohol and groping him, and of engaging in strange and inappropriate behavior with other children.

The case followed years of rumors about Jackson and young boys. In a TV documentary, he acknowledged sharing his bed with children, a practice he described as sweet and not at all sexual.

Despite the acquittal, the lurid allegations that came out in court took a fearsome toll on his career and image, and he fell into serious financial trouble.

Jackson's 13 No. 1 one hits on the Billboard charts put him behind only Presley, the Beatles and Mariah Carey, said Billboard magazine editorial director Bill Werde .

"He was on the eve of potentially redeeming his career a little bit," he said. "People might have started to think of him again in a different light." Early life

* Michael Jackson was born on August 29, 1958, in Gary, Indiana, the seventh of nine children. Five Jackson boys first performed together at a talent show when Michael was 6.

* Their group later became The Jackson Five, and when it was signed by Motown Records in the late 1960s, it underwent its final metamorphosis to become The Jackson 5. Jackson made his first solo album in 1972. Success

* Jackson released "Thriller" in 1982, which became a smash hit that yielded seven top 10 singles. The album sold 21 million copies in the United States and at least 27 million worldwide.

* The next year, he unveiled his signature "moonwalk" dance move while performing "Billie Jean" during an NBC special.

* Jackson's lifetime record sales tally is believed to be about 750 million. Accusations

* In 1993, Jackson was accused of sexually abusing a 13-year-old boy, and police raided his California ranch "Neverland."

* The same year, Jackson announced he had become addicted to painkillers and canceled a world tour to promote "Dangerous."

* He reached a settlement in 1994, later reported to be US$23 million, with the family of the boy he was accused of abusing. Facts about Michael Jackson Marriage and family

* In 1994, Jackson married Elvis Presley's only child, Lisa Marie, but the marriage ended in divorce in 1996. Jackson married Debbie Rowe the same year and had two children, before splitting in 1999. The couple never lived together.

* Jackson has three children named Prince Michael I, Paris Michael and Prince Michael II, known for his brief public appearance when his father held him over the railing of a hotel balcony, causing widespread criticism.

More controversy

* A television documentary "Living with Michael Jackson" was aired in 2003, saying that Jackson still had sleepovers with young boys and had his third child with a surrogate mother.

* Jackson went on trial in 2005 on charges of molesting a 13-year-old boy in 2003, as well as conspiring to abduct the boy.

* The four-month trial ended in June 2005 with Jackson being acquitted of all charges. Comeback?

* After several false dawns, Jackson and music promoter AEG Live announced he would perform 50 concerts at London's O2 Arena. Jackson had been due to start the concerts on July 13. Jackson had been rehearsing in the Los Angeles area for the London shows, which sold out within hours of going on sale in March. 'The way Elvis destroyed himself interests me'

Michael Jackson didn't want to be just a superstar. Like the Beatles, he wanted to be the biggest, the undisputed king. He wanted to topple the reigning man with the crown, Elvis.

In the end, Jackson came to resemble Elvis in both the best and worst ways -- supremely gifted and successful but also self-destructive and beset by demons. And like Elvis, he died way too young.

"It's just so weird. He even married Elvis' daughter," said author-music critic Greil Marcus, who wrote at length about Presley in his acclaimed cultural history, "Mystery Train."

Elvis Presley died a bloated middle-age man after overdosing on prescription drugs at home in 1977 at age 42. Jackson died on Thursday at age 50 after being rushed from his Los Angeles home to UCLA Medical Center.

Like Elvis, Jackson was once beautiful, outrageous, a revolutionary without politics who shook down the walls between black and white. He had the hits, the style, the ego, the talent.

He was the "King of Pop," and he needed only to fill in the life: He married Elvis' daughter. He bought the rights to some of Elvis' songs. Elvis owned Graceland, its name a symbol for a deliverance the singer prayed for until the end of his life.

Jackson did, and did not, want to be like Elvis. In "Moon Walk," a memoir published in 1988, Jackson insisted Elvis was not important to him growing up and that he was unhappy to learn a song he recorded with his brothers, "Heartbreak Hotel," shared the name of Presley's first national hit.

"As important as he was to music, black as well as white, he just wasn't an influence on me," he wrote. "I guess he was too early for me. Maybe it was timing more than anything else." Michael Jackson's health woes took center stage Over Michael Jackson's chart-topping music career, his health has commanded as much publicity as his hit songs.

Plastic surgery, mysterious hospitalizations and reports of pill popping have long plagued the King of Pop.

Jackson's unexpected death stunned the world despite his history of health problems -- some real and others rumored.

In the early 1990s, Jackson's dermatologist revealed the singer had a skin disorder known as vitiligo, which leads to white patches on the skin. Over the years, Jackson underwent numerous plastic surgeries, including a nose job.

Jackson was also widely reported to be addicted to painkillers from pain he developed after he was burned while filming a Pepsi commercial in 1984.

During his 2005 molestation trial in which he was acquitted, Jackson appeared gaunt and had recurring back problems he attributed to stress. The trial was interrupted several times by hospital visits.

Last year, a celebrity biographer claimed Jackson suffered from a rare respiratory disease and was in need of a lung transplant.

Chatter about Jackson's health surfaced again last month after his representatives postponed several of his London comeback shows, citing the need for more rehearsal time.

In his recent rehearsals for a comeback, Jackson was described as "very frail," but working hard.