This movie has been reviewed extensively. I would add to the other reviews with this ; yes the plot is complicated - consider that a bonus opportunity to watch it again ( and again ) until you take it all in. The banter is exquisite . Bogart is still married to his third wife , but the spark between Bogie and Bacall is apparent
to the audience. Bogie , as Marlowe , enjoys a magical existence ; every where he goes women swoon . He even engages a female taxi driver for a fare and she gives him her card and says call me anytime , nights are better , I work during the day. All the women Bogie encounters are attractive brunettes ; none are allowed to compete with Bacall in the hair colour department.
An unusual movie occurrence ; at one point Bogie and Bacall deliver lines at the same time , over each other . Couldn't possibly be done by accident , they would have just shot it again. As it is it adds to the confusion and tenseness of the scene. Now 66 years old it stands as a gem worth viewing.