Arlen is one of the few (possibly the only) composer Mercer has been able to work with so closely, for they held their meetings in Arlen's study. ``Some guys bothered me,'' Mercer has said. ``I couldn't write with them in the same room with me, but I could with Harold. He is probably our most original composer; he often uses very odd rhythms, which makes it difficult, and challenging, for the lyric writer.''

While Arlen and Mercer collaborated on Hot Nocturne, Mercer worked also with Arthur Schwartz on another film, Navy Blues. Arlen, too, worked on other projects at the same time with old friend Ted Koehler. Besides doing a single song, ``When the Sun Comes Out,'' they worked on the ambitious Americanegro Suite, for voices and piano, as well as songs for films.

The Americanegro Suite is in a sense an extension of the Cotton Club songs in that it is a collection of Negro songs, not for a night club, but for the concert stage. The work had its beginning in 1938 with an eight bar musical strain to which Koehler set the words ``There'll be no more work/There'll be no more worry,'' matching the spiritual feeling of the jot. This grew into the song ``Big Time Comin'.'' By September 1940 the suite had developed into a collection of six songs, ``four spirituals, a dream, and a lullaby.''

The Negro composer Hall Johnson studied the Americanegro Suite and said of it, ``Of all the many songs written by white composers and employing what claims to be a Negroid idiom in both words and music, these six songs by Harold Arlen and Ted Koehler easily stand far out above the rest. Thoroughly modern in treatment, they are at the same time, full of simple sincerity which invariably characterizes genuine Negro folk-music and are by no means to be confused with the average' Broadway Spirituals' which depend for their racial flavor upon sundry allusions to the 'Amen Corner', 'judgement day',' Gabriel's horn', and a frustrated devil -- with a few random 'Hallelujahs' thrown in for good measure.