"To have and have not" is the story of an American boat captain, Harry Morgan, in Cuba  who, at the end of the road, struggling with acute poverty and victimized by the so-called rich, decides to try something else and gets caught in the middle of a crime and finds himself in a desperate situation requiring some truly desperate measures. 

Here is Hemingway gone almost fully Hollywood or maybe Hollywood went Hemingway here after. 

Have an have not is the story of a fundamental struggle. A class warfare that has always existed from then upto to occupy wall street movement. Only that the struggle created envy and desire then but creates resentment and disdain now. 

This is very Hemingway. Mostly stripped off of dialogue, a short book of two action packed episodes, this book is very elemental. The code hero in all his glory. The noir mood where the final outcome is never in question only the means to it and what could be achieved while on the way. 

Hemingway tells without explaining and the mood builds almost to a claustrophobia, an oppressive boiler room. The only thing that matters is the code. The Hemingway code. And even then the book felt like a deviation from Hemingway's prior books. This is the most direct that Hemingway could have been. Written as two short stories (for Cosmopolitan and Esquire, strangely enough) that later got published as a single novel, probably explains why. 

Howard Hawks later made a film with the same name but a modified story with Humphrey Bogart and Lauren Bacall. Bogart seems like the obvious choice and you can envision him as Harry Morgan when you read the book without ever having seen the movie.