Honestly, I never read The Godfather novels. Seen the films so many times, but I should read the novels shouldn't I?

No.

(I figure most everyone else will respond that you SHOULD read the novel. I wanted to make sure you had the choice NOT TO read it).

I wouldn't say it's necessary even though it differs in some ways to the films don't get me wrong it's a great read but it's certainly not a necessity imo.

The GF novel is a unique piece of literature. I read it several times before I saw the film. As with just about any film that's based on a novel, knowledge of the novel's content helps to fill in the blanks for the film's viewers. Also, the back stories that the novel offers can fill out the characters, their motivations, relationships, etc. in the movie.

Read it and see what you think.

What Olivant said.

It's best to first watch the first two movies, then read the novel. Then finally watch part III.

The thing is, reading the novel first takes away the suprise effect of the movies, and may drastically reduce the overall impression, also because of the novel you will perceive the film more critically. The novel is great to read afterwards as it provides details that were left out of the films. It's the definitive background check.

On the other hand, the novel has some surprise effects which the film lacks, especially the deaths of ... and ...

Thanks. I was searching the same information since many months. Thanks for your hard work.