The document discusses the classical period of music between 1750-1820 and focuses on four prominent composers of that era. It describes how composers emphasized form and structure over emotion. The four composers highlighted are Gluck, who reformed opera; Haydn, considered the "father of the sonata" for developing symphonic structure; Mozart, a child prodigy and genius known for his operas like "The Marriage of Figaro"; and Beethoven, who is not described within the 3 sentence limit.