Fats Waller was an American jazz pianist, organist, composer, singer, and comedic entertainer. He was one of the most popular performers of the 1920s and 1930s, and his music is still enjoyed today. Waller was known for his improvisational skills and his ability to play the piano with both hands. He was also a prolific songwriter, having written over 400 songs. Waller was also a talented vocalist, and he often performed his own compositions. He was an influential figure in the development of jazz and popular music, and his influence can still be heard in modern music.