In 1928, Gershwin stopped all work and traveled to Europe with his brother Ayler. During his stay in Paris, Gershwin was touched by the local culture and wrote the famous "An American in Paris". The content describes a lonely and homesick American walking on the streets of Paris and experiencing a bustling, crowded and neon-filled world. Lonely night. After returning to New York, the entire piece was completed and premiered at Carnegie Hall in December of the same year. At the same time, Gershwin discovered a surprising phenomenon from his brother Ayler: Ayler's rich literary talent, novel, vivid and unconventional writing, which matched well with the new music he wrote. From then on, the two brothers relied on each other and cooperated closely. One wrote lyrics and the other composed music. They were respected by Americans as "Mr. Letters" and "Mr. Music" respectively. They grasped the pulse of the 20th century and together gave birth to mature American pop music.