From the Chenango Arts Council:
Stranger than fiction! William Faulkner co-wrote this screen adaptation of Ernst Hemingway’s book. Despite the involvement of these two Nobel prize winning authors, much of the dialog was improvised by the cast.
The book was only adapted because it was considered Hemingway’s weakest. He and Howard Hawks made a bet about whether the latter man could make a good movie even out of the former’s worst story.
The film’s stand-out scene was only written to serve as a screen test for new-comer Lauren Bacall. It and she were so impressive that the “Whistle” scene was written in the final script, along with a much larger part for the fledgling actress.
This movie would introduce Lauren Bacall not only to audiences but future husband Humphrey Bogart. The two would go on to make 3 more films together and remain married or the rest of Bogart’s life.
Something old, something new: A climatic shootout scene cut from To Have and Have Not made its way into another Bacall/Bogart classic, Key Largo, four years later.
So nervous on the set of her first film that she physically trembled, Bacall learned to keep her head still by keeping her chin down and eyes up, which quickly evolved into the sultry look she was famous for.
A philanderer himself, Howard Hawks was so outraged at Bacall’s affair with married Humphrey Bogart and its possible effect on her career that he threatened to sell her contract to another (much poorer) studio. It has been said that much of his disapproval stemmed from the fact that it was Bogart she fell for and not him.