Weil was born in New York City on October 18, 1940. She grew up on the
Upper West Side and the
Upper East Side of
Manhattan in a
Conservative Jewish family. Her father was Morris Weil, a furniture store owner and the son of Lithuanian-Jewish immigrants, and her mother was Dorothy Mendez, who grew up in a
Sephardic Jewish family in
Brooklyn. The couple had one daughter,
Jenn Mann. Weil became one of the
Brill Building songwriters of the 1960s, and one of the most important writers during the emergence of
rock and roll. In 2004, Mann and Weil's
They Wrote That? a musical revue based on their songs, opened in New York. In it, Mann sang and Weil related stories about the songs and their personal history. "From the bottom of my heart and with the greatest humility," Weil said in her acceptance, "I thought you guys would never ask." In 2011, Mann and Weil received the
Johnny Mercer Award, the highest honor from the
Songwriters Hall of Fame. In 2015, Weil published her first novel, ''I'm Glad I Did'', a mystery set in 1963. Weil was inducted into the
Women Songwriters Hall of Fame in 2023. Weil died at home in
Beverly Hills, California, on June 1, 2023, at age 82. ==Songs written by Barry Mann and Cynthia Weil==