On four different occasions, African-American friends expressed total surprise when I told them that "Harlem Nocturne" was composed by a white man, Earle Hagen.   They expressed amazement that somehow his melody, his configuration of notes, the harmony, the tempo, the rhythm captured the essence of the black experience.   Another thing - this song remains fresh and young while we don't.   It was perfectly fitting that Earle used this composition of his 40 years later as his theme for "Mike Hammer".