Mary Lou Williams shows how to scat on Mr. Rogers’ Neighborhood

Pianist, arranger and composer Mary Lou Williams had a career that started in the 1920s and spanned decades. Her output included swing, bebop and sacred music. “I’m the only living musician that has played all the eras,” Mary Lou confidently advised Marian McPartland in the debut 20 years ago of McPartland’s acclaimed radio broadcast, Piano Jazz. “Other musicians lived through the eras and they never changed their styles.”