Formidable from the first moment of her professional career, Mary Lou Williams’s position in the Andy Kirk Orchestra of the mid-Thirties was made clear in the title of one of its records: The Lady Who Swings the Band. She swung the band, all right, in that piece and "Mary’s Idea," "Walkin’ and Swinging’," "Twelfth Street Rag," and many others. She was not just the heart of the band but its arranging brain. She went on to write superb arrangements for Earl Hines, Benny Goodman, Tommy Dorsey, and Duke Ellington. In the 1960s and ’70s she composed full-scale religious works. Throughout her life, she was a masterful solo pianist. This 1978 concert three years before her death displays her range from slow blues, ragtime, and swing through impressionistic modernism. It includes two of her most famous compositions, "What’s Your Story Morning Glory" and "Little Joe from Chicago."