Close-up of the hands of jazz pianist Mary Lou Williams during a jam session held in New York City, 1943

© Gjon Mili/Getty Images

Close-up of the hands of jazz pianist Mary Lou Williams during a jam session held in New York City, 1943

You are seeing–and hearing, if you click the audio button on the lower-right corner of the homepage–the musical stylings of Mary Lou Williams, often called the first lady of the jazz keyboard. Williams was a composer, arranger, and pianist who recorded more than 100 records, collaborating with the likes of Dizzy Gillespie, Thelonious Monk, and Duke Ellington. She’s photographed here in 1943 by photographer Gjon Mili, who often hosted jazz jam sessions at his New York City studio.