Everybody's heard of this movie because of the famous title song, but almost nobody's ever seen it. It defies genre classification -- both a musical drama and a sort of missing link between the Warners gangster movies of the 1930s (mugs, molls, and rat-a-tat dialogue) and 1940s film noir (femme fatale, dark shadows, smoky atmosphere, seamy underside of life). It's a genuine one-of-a-kind movie that deserves to be much better remembered than it is.
However, one commenter here needs to refresh his memory; BLUES IN THE NIGHT has nothing whatever to do with the career of Jimmy Lunceford or any other famous musician of the period. It's about a small jazz combo, not a big band, and they begin and end the movie as obscure journeymen living from hand to mouth between gigs. GREAT CLASSIC ON DVD