With wife Valerie Simpson, the songwriter/producer/vocalist elevated the art of the duet.

As tributes poured in following the Aug. 22 death of singer/songwriter Nick Ashford, the word "legend" was frequently invoked.

It's a fitting salute to a talented artist who, together with his wife and writing/singing partner Valerie Simpson, penned some of the most iconic songs in popular music, including "Ain't No Mountain High Enough," "I'm Every Woman," "You're All I Need to Get By" and "Reach Out and Touch (Somebody's Hand)." As Ashford & Simpson, the pair also found success in front of the mic with such R&B hits as "Solid" and "Found a Cure."

"Nick had the rare ability to not only craft indelible music, but to make an indelible impression on everyone he met," Warner Music Group chairman Edgar Bronfman Jr. says. "As a composer and as a performer, he captured the essence of human emotion to make soulful music that was passionate, romantic, uplifting and unforgettable."

That creative legacy ignited a spate of Twitter tributes after the 70-year-old Ashford's death from throat cancer at New York's Presbyterian Hospital was announced by friend and former publicist Liz Rosenberg. Among those sharing their condolences and thoughts were Lenny Kravitz, Raekwon and Living Colour'scq Vernon Reid, who tweeted, "Nobody did it better." Stephen Hill, president of music programming and specials at BET, summed up Ashford's essence in three words: "lover of love."

Born on May 4, 1941, in Fairfield, S.C., Ashford grew up in Willow Run, Mich., where he began honing his skills as a singer and songwriter while working with the gospel choir at the local Baptist church. After moving to New York in the early '60s, Ashford met writing partner and future wife Simpson at Harlem's White Rock Baptist Church.

The pair partnered with former Ikette Joshie "Jo" Armstead and began writing songs for Florence Greenberg's Scepter/Wand label, including Maxine Brown's "One Step at a Time" and Ronnie Milsap's "Never Had It So Good."

In 1966, Ashford, Simpson and Armstead scored a No. 1 R&B single with Ray Charles' irreverent turn on their "Let's Go Get Stoned." That success prompted Motown Records chief Berry Gordy to sign Ashford & Simpson as staff writers and producers. With love as the central theme, the pair penned a string of melodic, gospel-influenced soul/pop gems that helped elevate another emerging duo: Marvin Gaye and Tammi Terrell. Beginning in 1967 with "Ain't No Mountain High Enough," the foursome reeled off such additional classics as "You're All I Need to Get By," "Ain't Nothing Like the Real Thing" and "Your Precious Love."

Other Motown acts to record Ashford & Simpson songs were Gladys Knight & the Pips, Smokey Robinson & the Miracles and the Marvelettes.

One of the acts that performed early Ashford & Simpson compositions was the 5thcq Dimension. Former members Marilyn McCoo and Billy Davis Jr. recall that producer Bones Howe brought "California Soul," released in 1969, to the group's attention. "We were so excited to hear this Ashford & Simpson song," McCoo says. "We thought it might open up the potential for us to have a stronger R&B following. They were an amazing songwriting couple."

Another highlight of Ashford & Simpson's years at Motown was their work with Diana Ross. They produced-and composed nearly all of the songs for-three of the former Supreme's albums: her 1970 self-titled solo debut, which featured her first soaring, chart-topping remake of "Ain't No Mountain High Enough"; Surrender in 1971; and The Boss in 1979.

Eager to relaunch their own singing careers that started in the mid-'60s, Ashford & Simpson signed with Warner Bros. in 1973, when they released their first album on the label, Gimme Something Real.

Married in 1974, the pair embodied the perfect recording merger: songwriter/producers who were just as talented vocally, with Simpson's siren call meshing effortlessly with Ashford's falsetto response. Still keeping love as their central theme, the duo broke into the R&B top 20 in 1977 with "Send It." Subsequent hits-and dance club fixtures-included "It Seems to Hang On" and "Found a Cure."

Moving to Capitol in the early '80s, Ashford & Simpson landed their biggest R&B and pop hit with 1984's "Solid." Along the way, the duo joined Chaka Khan as featured guests on Quincy Jones' No. 1 R&B single, "Stuff Like That," in 1978. Khan herself topped that tally the same year with her cover of the Ashford & Simpson anthem "I'm Every Woman," later covered by Whitney Houston in 1992 on the "Bodyguard" soundtrack.

In 1996, Ashford & Simpson opened the Sugar Bar, a restaurant and live entertainment venue in Manhattan that became known for its popular open-mic sessions often hosted by the pair. Inducted into the Songwriters Hall of Fame in 2002, Ashford & Simpson most recently received songwriting credit on Amy Winehouse's "Tears Dry on Their Own," which borrows liberally from the music ofnot a sample "Ain't No Mountain High Enough."

At press time, funeral arrangements hadn't yet been announced. In addition to his wife, Ashford is survived by daughters Nicole and Asia.••••

Additional reporting by Fred Bronson in Los Angeles.