Ernest Hemingway didn't think his book could be translated into a movie. He was right. Director Howard Hawks instead made a movie with his book's title and similar characters. I don't hold that against him. I never read the book and very little Hemingway in general.
Bogart is Captain Morgan. Not THAT Captain Morgan, just A captain Morgan. Steve Morgan. Or Henry Morgan. Whatever, it doesn't matter. He takes rich people and his drunkard friend (Walter Brennan) out for fishing trips. To complicate this heaven on Earth, Nazis, the resistance, and a hot chick enter his life. Basically, Casablanca with a slightly different setting.
Morgan doesn't want to get involved with the resistance, but he is short on cash. He acts tough guy, woos the chick (Lauren Bacall), and makes them Nazis pay. Typical of what we expect from the man.
Not much more to say, really. Enjoyable. Not as good as Casablanca, but still good. AMRU 3.5.