How does the book, To Kill a Mockingbird, differ from the movie?
In the beginning, we miss many of the school experiences that Scout encounters in the book. We never really meet Miss Caroline or see her struggle to educate the 1st grade. Therefore, the issue with the cootie and Burris' Ewell never gets addressed in the beginning. We do get to see Walter Cunningham go to Scout's for lunch. The Christmas scene at Finch's landing gets skipped. Miss Stephanie Crawford plays the role of both herself and Miss Rachel Haverford, thus the Dill character calls her Aunt Stephanie.
Much of the description of the Finch background and narration from Scout about their lives and times gets over-looked. The scene with her describing the waste that school became, many moments with Dill, and the talks about gentle-breeding get skipped.
I think if something felt like it was not a part of the Boo Radley storyline or the trial storyline, it got skipped. Most of these instances were the Finch family shadings. These are likely some of the most important parts that Lee intended to point out in her book because it is from these perspectives that we watch a child mature and grow in to a moral and humane adult writer.