Dorothy Fields wrote 500 songs and 19 Broadway musicals including Sweet Charity and Annie Get Your Gun.
She also wrote for film, including the movie Swing Time, starring Fred Astaire and Ginger Rogers, for which she was the first female lyricist to win an Oscar.
Martha asks actress Angela Richards and Dorothy Fields' expert, Jon Aldous, how she came to be such a success and why we don't know more about her. Dorothy Fields Forever opens at the Kings Head Theatre, 115 Upper Street Islington, London on June 11 - 21 July. Box office 020 7226 1916