First, rent Gary Sinise' 1992 version.
Then read the book, then watch this version of the story. You probably wont make it all the way through. I read the book, first, as a kid... and not because I was assigned to read it but because I liked to read.
Then I saw this movie on late-night TV, you know when almost every local channel ran movies on the weekend.... and I thought it was poor.
In the years since, I've seen TV adaptations and TV broadcasts of stage play versions. None carried the full flavor and emotion of the book.
It is widely accepted that thirties cinema was the peak of the art. This film, whether the exception or the model, proves otherwise.
Gary Sinise did a far better and more faithful adaptation of the book. If you were to buy one version, I suspect it will be the 1992 film.