Louis Horst (1884-1964) was an influential American composer, pianist, and music educator, primarily associated with the modern dance movement. He is best known for his collaboration with renowned dancers and choreographers, particularly Martha Graham, with whom he developed a close artistic partnership. Horst's work is often categorized within the realms of concert music and modern dance, blending classical elements with innovative techniques. Notable works include his compositions for Graham's groundbreaking dances, such as "Appalachian Spring," where his music played a crucial role in enhancing the narrative and emotional depth of the choreography. Horst's 1930s compositions, including "The Four Seasons" and "The Dance," also showcase his unique style. Horst's impact on music and dance is significant; he is credited with helping to establish the role of music in modern dance as a critical element, rather than just an accompaniment. His teachings and compositions influenced generations of dancers and choreographers, paving the way for future collaborations between music and dance. Horst's legacy is evident in the continued integration of live music in dance performances and the evolution of dance as an art form.