Nancy Wilson, the Grammy-winning "song stylist" and torch singer whose polished pop-jazz vocals made her a million-selling recording artist and top concert performer, has died at age 81.

Her manager Devra Hall Levy said that Wilson died peacefully after a long illness at her home in Pioneertown, a California desert community near Joshua Tree National Park. 

Influenced by Dinah Washington, Nat King Cole and other stars, Wilson covered everything from jazz standards to "Little Green Apples,'' and in the 1960s alone released eight albums that reached the top 20 on Billboard's pop charts. 

Sometimes elegant and understated, or quick and conversational, she was best known for such songs as her breakthrough, "Guess Who I Saw Today,'' and the 1964 hit "(You Don't Know) How Glad I Am,'' which drew upon Broadway, pop and jazz.

Wilson retired from touring in 2011. 

The Associated Press contributed to this report.