Gus Kahn, one of the most prolific and successful songwriters of the twentieth century, wrote lyrics to more than two thousand songs, averaging six hits a year for twenty years. Writing the words to songs was a life-consuming passion for him. He would frequently stop whatever he was doing and scribble the words to a new song on any available writing surface, be it a golf scorecard or a napkin. In the middle of conversations he would quickly write down a lyric, then resume the conversation as if he had never left it. Kahn liked to write lyrics for melodies that had already been written, and he matched vernacular phrases to the popular tunes of three decades. His versatility led to success on Broadway in the 1920s and then even more acclaim in Hollywood in the 1930s as a songwriter for movies. Long after their heyday, Kahn's songs...