Oscar Hammerstein I was a German-born businessman, theater impresario, and composer in New York City. His passion for opera led him to open several opera houses, and he rekindled opera's popularity in America. He was the grandfather of American playwright/lyricist Oscar Hammerstein II and the father of theater manager William Hammerstein and American producer Arthur Hammerstein.

Oscar Greeley Clendenning Hammerstein II was an American lyricist, librettist, theatrical producer, and director in musical theater for nearly 40 years. He won eight Tony Awards and two Academy Awards for Best Original Song. Many of his songs are standard repertoire for vocalists and jazz musicians. He co-wrote 850 songs.