Rick Wright, 65; Founding Member of Pink Floyd

Rick Wright, 65, who helped start the British rock band Pink Floyd and whose keyboard skills brought a haunting quality to its most successful albums, "The Dark Side of the Moon," "Wish You Were Here" and "The Wall," died of cancer Sept. 15 at his home in London.

Starting in the late 1960s, Pink Floyd challenged the Rolling Stones and the Beatles as dynamic English musical exports. Decades later, Pink Floyd's citation for the Rock and Roll Hall of Fame said the band "carried rock and roll into a dimension that was more cerebral and conceptual than what preceded it."

Brooding, drug-fueled lyrics, "space-rock" sound effects and mesmerizing visual flourishes in concert turned Pink Floyd into a cult favorite during a peak counterculture moment. Filmmakers such as Michelangelo Antonioni ("Zabriskie Point," 1970) hired the band to create a psychedelic mood that simulated the mind-altering effects of LSD and other hallucinogenic drugs.

Subsequent albums exploring bleak messages about societal alienation -- as well as aging, money and time -- catapulted the band to the front rank of commercial success while showing that rock music could address serious adult themes. "The Dark Side of the Moon" (1973) was on Billboard magazine's list of top long-playing releases for more than 500 weeks.

Mr. Wright shared writing credit on songs including "Time" and "Us and Them" for "The Dark Side of the Moon." He also helped compose "Shine On You Crazy Diamond" for the album "Wish You Were Here" (1975), a work meant to pay tribute to former bandmate Syd Barrett.

Singer-guitarist Barrett, whose already fragile mental health was devastated by drug use, left the group in the late 1960s and was replaced by David Gilmour. Besides Mr. Wright and Gilmour, Pink Floyd's principal lineup included songwriter Roger Waters on bass and Nick Mason on drums.

With the group's popularity surging by the late 1970s, Mr. Wright attempted a solo album, "Wet Dream" (1978), that leaned heavily on Pink Floyd's slow, meditative trademark sound.

The recording sold poorly, and he was back the next year to make "The Wall." He formally left the band during production, citing artistic tensions with Waters, but in an unusual agreement came back to Pink Floyd as a contract musician.

"Roger's ego was getting bigger and bigger," he told the Boston Globe in 1997. "He said he wanted me out because I hadn't produced any material: 'If he doesn't leave, I'm going to withdraw "The Wall" and make it a solo project.' Dave and Nick Mason, the drummer, were very scared, too. It was a nightmare for all us."

Waters eventually went in his own direction and sued unsuccessfully when the others formed a post-Waters version of the rock band under the same name in the late 1980s.

Mr. Wright continued an affiliation with Pink Floyd that lasted on and off for several more years and worked on its releases "A Momentary Lapse of Reason" (1987), and "The Division Bell" (1994).

Despite the acrimony between Waters and the others, all four Pink Floyd bandmates reunited in July 2005 to perform at the Live 8 benefit concert in London's Hyde Park.