Scott Joplin's music is best known for its ragtime and RAG genres. Ragtime is a style of music that originated in the late 19th century, characterized by syncopated rhythms and melodies. It was popularized by Scott Joplin, who wrote some of the most famous ragtime pieces such as 'The Entertainer' and 'Maple Leaf RAG'. RAG is a genre of music that developed from ragtime, featuring more complex rhythms and improvisation. It is often considered to be a precursor to jazz.