Ms. Houston's longtime mentor, Clive Davis, was to hold his annual concert and dinner Saturday, and a representative of the show said it would proceed. Ms. Houston was supposed to have appeared at the gala.
Ms. Houston had been at rehearsals for the show Thursday, coaching singers Brandy and Monica, according to a person who was at the event but was not authorized to speak publicly about it. The person said that Ms. Houston looked disheveled, was sweating profusely, and smelled of liquor and cigarettes.
Rosen said police received a 911 call from hotel security about Ms. Houston at 3:43 p.m. local time Saturday. Paramedics, already at the hotel because of a Grammy party, unsuccessfully tried to resuscitate her, the lieutenant said.
The Rev. Al Sharpton said he would call for a national prayer Sunday morning during a service at Second Baptist Church in Los Angeles.
"The morning of the Grammys, the world should pause and pray for the memory of a gifted songbird," Sharpton said in a written statement.
At her peak, Ms. Houston was the golden girl of the music industry. From the mid-1980s to the late 1990s, she was one of the world's best-selling artists. She wowed audiences with effortless, powerful, and peerless vocals that were rooted in the church.
Her success carried her beyond music to movies, where she starred in hits such as The Bodyguard and Waiting to Exhale.
She had the perfect voice and the perfect image: a gorgeous singer who maintained perfect poise.
She influenced a generation of younger singers, including Christina Aguilera and Mariah Carey, who when she first came out sounded so much like Ms. Houston that many thought it was Ms. Houston.
But by the end of her career, Ms. Houston had become a stunning cautionary tale of the toll of drug use. Her album sales plummeted and the hits stopped coming; her once serene image was shattered by a wild demeanor and bizarre public appearances. She confessed to abusing cocaine, marijuana, and pills, and her once-pristine voice became raspy and hoarse, unable to hit the high notes.
"The biggest devil is me. I'm either my best friend or my worst enemy," Ms. Houston told ABC's Diane Sawyer in a 2002 interview with then-husband Brown by her side.
It was a tragic fall for a superstar who had sold more than 55 million records in the United States alone.
Born in Newark, N.J., on Aug. 9, 1963, she was the daughter of gospel singer Cissy Houston, cousin of 1960s pop diva Dionne Warwick, and the goddaughter of Aretha Franklin.
Ms. Houston first started singing in the church as a child. In her teens, she sang backup for Chaka Khan, Jermaine Jackson, and others, in addition to modeling. It was around then that Davis first heard Ms. Houston perform.
"The time that I first saw her singing in her mother's act in a club . . . it was such a stunning impact," Davis told Good Morning America.
"To hear this young girl breathe such fire into this song. I mean, it really sent the proverbial tingles up my spine," he added.
Before long, the rest of the country would feel it, too. Ms. Houston made her album debut in 1985 with Whitney Houston, which sold millions and spawned hit after hit. "Saving All My Love for You" brought her her first Grammy, for best female pop vocal. "How Will I Know," "You Give Good Love," and "The Greatest Love of All" also became hit singles.
Another multiplatinum album, Whitney, came out in 1987 and included hits such as "Where Do Broken Hearts Go" and "I Wanna Dance With Somebody."
Her decision not to follow the more soulful inflections of singers like Franklin drew criticism from some who saw her as playing down her black roots to go pop and reach white audiences. The criticism would become a refrain through much of her career. She was even booed during the Soul Train Awards in 1989.
Some saw her 1992 marriage to former New Edition member Brown as an attempt to answer those critics. It seemed to be an odd union; she was seen as pop's pure princess while he had a bad-boy image, and already had children of his own. (The couple had a daughter, Bobbi Kristina, in 1993.)
In 1992, she became a star in the acting world with The Bodyguard. Despite mixed reviews, the story of a singer (Ms. Houston) guarded by a former Secret Service agent (Kevin Costner) was an international success.
It also gave her perhaps her most memorable hit: a searing, stunning rendition of Dolly Parton's "I Will Always Love You," which sat atop the charts for weeks. It won the Grammy for record of the year and best female pop vocal, and the Bodyguard soundtrack was named album of the year.
She returned to the big screen in 1995-96 with Waiting to Exhale and The Preacher's Wife. Both spawned soundtrack albums, and another hit studio album, My Love Is Your Love, in 1998, brought her a Grammy for best female R&B vocal for the song "It's Not Right But It's Okay."
But during these career and personal highs, Ms. Houston was using drugs. In an interview with Oprah Winfrey in 2010, she said that by the time The Preacher's Wife was released, "[doing drugs] was an everyday thing. . . . I would do my work, but after I did my work, for a whole year or two, it was every day. . . . I wasn't happy by that point in time. I was losing myself."
In the interview, Ms. Houston blamed her unhappiness on her rocky marriage, which included a charge of domestic abuse against Brown in 1993. They divorced in 2007.
Ms. Houston would go to rehab twice before she would declare herself drug-free to Winfrey in 2010.
Her crude behavior and jittery appearance on the reality show Being Bobby Brown was an example of her sad decline. Her Sawyer interview, where she declared "crack is whack," was often parodied.
Ms. Houston staged what seemed to be a successful comeback with the 2009 album I Look to You. The album debuted on the top of the charts, and went platinum.
Things soon fell apart. A concert to promote the album on Good Morning America went awry as Ms. Houston's voice sounded ragged and off-key. She said an interview with Winfrey had strained her voice.
See a Whitney Houston photo galley and more at philly.com.