Send in the Clowns

Of Stephen Sondheim's 800+ songs, this is the one that became a megahit. It only achieved popularity with recordings by Frank Sinatra and, later, Judy Collins. Sondheim added a verse for a 1985 Barbra Streisand recording.

The song was written for actress Glynis Johns, who had a breathy voice and a limited tessitura -- Sondheim made sure the song had short phrases and a small music range (only about an octave).